The mesencephalic dopaminergic (mDA) cell system is composed of two major groups of projecting cells in the Substantia Nigra (SN) (A9 neurons) and the Ventral Tegmental Area (VTA) (A10 cells). Selective degeneration of A9 neurons occurs in Parkinson's disease (PD) while abnormal function of A10 cells has been linked to schizophrenia, attention deficit and addiction. The molecular basis that underlies selective vulnerability of A9 and A10 neurons is presently unknown.
Next-generation sequencing experiments have shown that microRNAs (miRNAs) are expressed in many different isoforms (isomiRs), whose biological relevance is often unclear. We found that mature miR-21, the most widely researched miRNA because of its importance in human disease, is produced in two prevalent isomiR forms that differ by 1 nt at their 3' end, and moreover that the 3' end of miR-21 is posttranscriptionally adenylated by the noncanonical poly(A) polymerase PAPD5. PAPD5 knockdown caused an increase in the miR-21 expression level, suggesting that PAPD5-mediated adenylation of miR-21 leads to its degradation. Exoribonuclease knockdown experiments followed by small-RNA sequencing suggested that PARN degrades miR-21 in the 3'-to-5' direction. In accordance with this model, microarray expression profiling demonstrated that PAPD5 knockdown results in a down-regulation of miR-21 target mRNAs. We found that disruption of the miR-21 adenylation and degradation pathway is a general feature in tumors across a wide range of tissues, as evidenced by data from The Cancer Genome Atlas, as well as in the noncancerous proliferative disease psoriasis. We conclude that PAPD5 and PARN mediate degradation of oncogenic miRNA miR-21 through a tailing and trimming process, and that this pathway is disrupted in cancer and other proliferative diseases.
Transcriptional Regulatory Networks (TRNs) coordinate multiple transcription factors (TFs) in concert to maintain tissue homeostasis and cellular function. The re-establishment of target cell TRNs has been previously implicated in direct trans-differentiation studies where the newly introduced TFs switch on a set of key regulatory factors to induce de novo expression and function. However, the extent to which TRNs in starting cell types, such as dermal fibroblasts, protect cells from undergoing cellular reprogramming remains largely unexplored. In order to identify TFs specific to maintaining the fibroblast state, we performed systematic knockdown of 18 fibroblast-enriched TFs and analyzed differential mRNA expression against the same 18 genes, building a Matrix-RNAi. The resulting expression matrix revealed seven highly interconnected TFs. Interestingly, suppressing four out of seven TFs generated lipid droplets and induced PPARG and CEBPA expression in the presence of adipocyte-inducing medium only, while negative control knockdown cells maintained fibroblastic character in the same induction regime. Global gene expression analyses further revealed that the knockdown-induced adipocytes expressed genes associated with lipid metabolism and significantly suppressed fibroblast genes. Overall, this study reveals the critical role of the TRN in protecting cells against aberrant reprogramming, and demonstrates the vulnerability of donor cell's TRNs, offering a novel strategy to induce transgene-free trans-differentiations.
Cap analysis of gene expression (CAGE) provides accurate high-throughput measurement of RNA expression. By the large-scale analysis of 5' end of transcripts using CAGE method, it enables not only determination of the transcription start site but also prediction of promoter region. Here we provide a protocol for the construction of no-amplification non-tagging CAGE libraries for Illumina next-generation sequencers (nAnT-iCAGE). We have excluded the commonly used PCR amplification and cleavage of restriction enzyme to eliminate any potential biases. As a result, we achieved less biased simple preparation process.
Cap analysis of gene expression (CAGE) is a sequencing based technology to capture the 5' ends of RNAs in a biological sample. After mapping, a CAGE peak on the genome indicates the position of an active transcriptional start site (TSS) and the number of reads correspond to its expression level. CAGE is prominently used in both the FANTOM and ENCODE project but presently there is no software package to perform the essential data processing steps.
Murine double minute 2 (MDM2) is a negative regulator of p53. A single-nucleotide polymorphism (SNP) (rs2279744: c.309T>G) in the promoter region of the MDM2 gene has been shown to result in higher levels of MDM2 RNA and protein. Regarding the contribution of c.309T>G in the MDM2 gene to the lung cancer risk, previous studies are conflicting. In order to evaluate the association between c.309T>G and the lung cancer risk, a case-control study was performed. The MDM2 genotypes were determined in 762 lung cancer patients and in 700 cancer-free control subjects using the Smart Amplification Process. Statistical adjustment was performed for gender, age and pack-years of smoking. The distributions of c.309T>G (T/T, T/G, G/G) were 20.1, 49.7, 30.2% in the case group and 21.7, 47.9, 30.4% in the healthy-control group. There were no overall associations between the MDM2 genotypes and the risk of lung cancer [T/G genotype: Adjusted odds ratio (AOR), 1.30; 95% confidence interval (CI), 0.88-1.93; and G/G genotype: AOR, 1.18; 95% CI, 0.78-1.80]. The subgroup analysis of gender, histology, smoking status and epidermal growth factor receptor mutation status also indicated that there was no association with lung cancer. Additionally, the genotypes did not have an effect on the age at the time of diagnosis of lung cancer (P=0.25). In conclusion, the G allele frequency in the lung cancer cases was 0.551, which was similar to other studies. The results of the present study suggest that the c.309T>G is not significantly associated with lung cancer.
Mesenchymal stem/stromal cells (MSCs) are the precursors of various cell types that compose both normal and cancer tissue microenvironments. In order to support the widely diversified parenchymal cells and tissue organization, MSCs are characterized by a large degree of heterogeneity, although available analyses of molecular and transcriptional data do not provide clear evidence. We have isolated MSCs from high-grade serous ovarian cancers (HG-SOCs) and various normal tissues (N-MSCs), demonstrated their normal genotype and analyzed their transcriptional activity with respect to the large comprehensive FANTOM5 sample dataset. Our integrative analysis conducted against the extensive panel of primary cells and tissues of the FANTOM5 project allowed us to mark the HG-SOC-MSCs CAGE-seq transcriptional heterogeneity and to identify a cell-type-specific transcriptional activity showing a significant relationship with primary mesothelial cells. Our analysis shows that MSCs isolated from different tissues are highly heterogeneous. The mesothelial-related gene signature identified in this study supports the hypothesis that HG-SOC-MSCs are bona fide representatives of the ovarian district. This finding indicates that HG-SOC-MSCs could actually derive from the coelomic mesothelium, suggesting that they might be linked to the epithelial tumor through common embryological precursors. Stem Cells 2014;32:2998-3011.
Enhancers control the correct temporal and cell-type-specific activation of gene expression in multicellular eukaryotes. Knowing their properties, regulatory activity and targets is crucial to understand the regulation of differentiation and homeostasis. Here we use the FANTOM5 panel of samples, covering the majority of human tissues and cell types, to produce an atlas of active, in vivo-transcribed enhancers. We show that enhancers share properties with CpG-poor messenger RNA promoters but produce bidirectional, exosome-sensitive, relatively short unspliced RNAs, the generation of which is strongly related to enhancer activity. The atlas is used to compare regulatory programs between different cells at unprecedented depth, to identify disease-associated regulatory single nucleotide polymorphisms, and to classify cell-type-specific and ubiquitous enhancers. We further explore the utility of enhancer redundancy, which explains gene expression strength rather than expression patterns. The online FANTOM5 enhancer atlas represents a unique resource for studies on cell-type-specific enhancers and gene regulation.
Naturally occurring regulatory T (Treg) cells, which specifically express the transcription factor forkhead box P3 (Foxp3), are engaged in the maintenance of immunological self-tolerance and homeostasis. By transcriptional start site cluster analysis, we assessed here how genome-wide patterns of DNA methylation or Foxp3 binding sites were associated with Treg-specific gene expression. We found that Treg-specific DNA hypomethylated regions were closely associated with Treg up-regulated transcriptional start site clusters, whereas Foxp3 binding regions had no significant correlation with either up- or down-regulated clusters in nonactivated Treg cells. However, in activated Treg cells, Foxp3 binding regions showed a strong correlation with down-regulated clusters. In accordance with these findings, the above two features of activation-dependent gene regulation in Treg cells tend to occur at different locations in the genome. The results collectively indicate that Treg-specific DNA hypomethylation is instrumental in gene up-regulation in steady state Treg cells, whereas Foxp3 down-regulates the expression of its target genes in activated Treg cells. Thus, the two events seem to play distinct but complementary roles in Treg-specific gene expression.
CAGE (cap analysis gene expression) and RNA-seq are two major technologies used to identify transcript abundances as well as structures. They measure expression by sequencing from either the 5' end of capped molecules (CAGE) or tags randomly distributed along the length of a transcript (RNA-seq). Library protocols for clonally amplified (Illumina, SOLiD, 454 Life Sciences [Roche], Ion Torrent), second-generation sequencing platforms typically employ PCR preamplification prior to clonal amplification, while third-generation, single-molecule sequencers can sequence unamplified libraries. Although these transcriptome profiling platforms have been demonstrated to be individually reproducible, no systematic comparison has been carried out between them. Here we compare CAGE, using both second- and third-generation sequencers, and RNA-seq, using a second-generation sequencer based on a panel of RNA mixtures from two human cell lines to examine power in the discrimination of biological states, detection of differentially expressed genes, linearity of measurements, and quantification reproducibility. We found that the quantified levels of gene expression are largely comparable across platforms and conclude that CAGE and RNA-seq are complementary technologies that can be used to improve incomplete gene models. We also found systematic bias in the second- and third-generation platforms, which is likely due to steps such as linker ligation, cleavage by restriction enzymes, and PCR amplification. This study provides a perspective on the performance of these platforms, which will be a baseline in the design of further experiments to tackle complex transcriptomes uncovered in a wide range of cell types.
Human blood monocytes comprise at least 3 subpopulations that differ in phenotype and function. Here, we present the first in-depth regulome analysis of human classical (CD14(++)CD16(-)), intermediate (CD14(+)CD16(+)), and nonclassical (CD14(dim)CD16(+)) monocytes. Cap analysis of gene expression adapted to Helicos single-molecule sequencing was used to map transcription start sites throughout the genome in all 3 subsets. In addition, global maps of H3K4me1 and H3K27ac deposition were generated for classical and nonclassical monocytes defining enhanceosomes of the 2 major subsets. We identified differential regulatory elements (including promoters and putative enhancers) that were associated with subset-specific motif signatures corresponding to different transcription factor activities and exemplarily validated novel downstream enhancer elements at the CD14 locus. In addition to known subset-specific features, pathway analysis revealed marked differences in metabolic gene signatures. Whereas classical monocytes expressed higher levels of genes involved in carbohydrate metabolism, priming them for anaerobic energy production, nonclassical monocytes expressed higher levels of oxidative pathway components and showed a higher mitochondrial routine activity. Our findings describe promoter/enhancer landscapes and provide novel insights into the specific biology of human monocyte subsets.
Mast cells (MCs) mature exclusively in peripheral tissues, hampering research into their developmental and functional programs. Here, we employed deep cap analysis of gene expression on skin-derived MCs to generate the most comprehensive view of the human MC transcriptome ever reported. An advantage is that MCs were embedded in the FANTOM5 project, giving the opportunity to contrast their molecular signature against a multitude of human samples. We demonstrate that MCs possess a unique and surprising transcriptional landscape, combining hematopoietic genes with those exclusively active in MCs and genes not previously reported as expressed by MCs (several of them markers of unrelated tissues). We also found functional bone morphogenetic protein receptors transducing activatory signals in MCs. Conversely, several immune-related genes frequently studied in MCs were not expressed or were weakly expressed. Comparing MCs ex vivo with cultured counterparts revealed profound changes in the MC transcriptome in in vitro surroundings. We also determined the promoter usage of MC-expressed genes and identified associated motifs active in the lineage. Befitting their uniqueness, MCs had no close relative in the hematopoietic network (also only distantly related with basophils). This rich data set reveals that our knowledge of human MCs is still limited, but with this resource, novel functional programs of MCs may soon be discovered.
CD4(+)CD25(+)FOXP3(+) human regulatory T cells (Tregs) are essential for self-tolerance and immune homeostasis. Here, we describe the promoterome of CD4(+)CD25(high)CD45RA(+) naïve and CD4(+)CD25(high)CD45RA(-) memory Tregs and their CD25(-) conventional T-cell (Tconv) counterparts both before and after in vitro expansion by cap analysis of gene expression (CAGE) adapted to single-molecule sequencing (HeliScopeCAGE). We performed comprehensive comparative digital gene expression analyses and revealed novel transcription start sites, of which several were validated as alternative promoters of known genes. For all in vitro expanded subsets, we additionally generated global maps of poised and active enhancer elements marked by histone H3 lysine 4 monomethylation and histone H3 lysine 27 acetylation, describe their cell type-specific motif signatures, and evaluate the role of candidate transcription factors STAT5, FOXP3, RUNX1, and ETS1 in both Treg- and Tconv-specific enhancer architectures. Network analyses of gene expression data revealed additional candidate transcription factors contributing to cell type specificity and a transcription factor network in Tregs that is dominated by FOXP3 interaction partners and targets. In summary, we provide a comprehensive and easily accessible resource of gene expression and gene regulation in human Treg and Tconv subpopulations.
In development, epigenetic mechanisms such as DNA methylation have been suggested to provide a cellular memory to maintain multipotency but also stabilize cell fate decisions and direct lineage restriction. In this study, we set out to characterize changes in DNA methylation and gene expression during granulopoiesis using 4 distinct cell populations ranging from the oligopotent common myeloid progenitor stage to terminally differentiated neutrophils. We observed that differentially methylated sites (DMSs) generally show decreased methylation during granulopoiesis. Methylation appears to change at specific differentiation stages and overlap with changes in transcription and activity of key hematopoietic transcription factors. DMSs were preferentially located in areas distal to CpG islands and shores. Also, DMSs were overrepresented in enhancer elements and enriched in enhancers that become active during differentiation. Overall, this study depicts in detail the epigenetic and transcriptional changes that occur during granulopoiesis and supports the role of DNA methylation as a regulatory mechanism in blood cell differentiation.
To explore the estrogen-regulated genes genome-widely in breast cancer, cap analysis of gene expression (CAGE) sequencing was performed in MCF-7 cells under estrogen treatment. Estrogen-regulated expressional changes were found in 1537 CAGE tag clusters (TCs) (?1.5 or ?0.66-folds). Among them, 15 TCs were situated in the vicinity of (?10 kb) reported estrogen receptor-binding sites. Knockdown experiments of the 15 TC-associated genes demonstrated that the genes such as RAMP3, ISOC1 and GPRC5C potentially regulate the growth or migration of MCF-7 cells. These results suggest that CAGE sequencing will reveal novel estrogen target genes in breast cancer.
Regulated transcription controls the diversity, developmental pathways and spatial organization of the hundreds of cell types that make up a mammal. Using single-molecule cDNA sequencing, we mapped transcription start sites (TSSs) and their usage in human and mouse primary cells, cell lines and tissues to produce a comprehensive overview of mammalian gene expression across the human body. We find that few genes are truly 'housekeeping', whereas many mammalian promoters are composite entities composed of several closely separated TSSs, with independent cell-type-specific expression profiles. TSSs specific to different cell types evolve at different rates, whereas promoters of broadly expressed genes are the most conserved. Promoter-based expression analysis reveals key transcription factors defining cell states and links them to binding-site motifs. The functions of identified novel transcripts can be predicted by coexpression and sample ontology enrichment analyses. The functional annotation of the mammalian genome 5 (FANTOM5) project provides comprehensive expression profiles and functional annotation of mammalian cell-type-specific transcriptomes with wide applications in biomedical research.
Standard culture of human induced pluripotent stem cells (hiPSCs) requires basic Fibroblast Growth Factor (bFGF) to maintain the pluripotent state, whereas hiPSC more closely resemble epiblast stem cells than true naïve state ES which requires LIF to maintain pluripotency. Here we show that chemokine (C-C motif) ligand 2 (CCL2) enhances the expression of pluripotent marker genes through the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) protein. Moreover, comparison of transcriptomes between hiPSCs cultured with CCL2 versus with bFGF, we found that CCL2 activates hypoxia related genes, suggesting that CCL2 enhanced pluripotency by inducing a hypoxic-like response. Further, we show that hiPSCs cultured with CCL2 can differentiate at a higher efficiency than culturing with just bFGF and we show CCL2 can be used in feeder-free conditions in the absence of LIF. Taken together, our finding indicates the novel functions of CCL2 in enhancing its pluripotency in hiPSCs.
Next generation sequencing based technologies are being extensively used to study transcriptomes. Among these, cap analysis of gene expression (CAGE) is specialized in detecting the most 5' ends of RNA molecules. After mapping the sequenced reads back to a reference genome CAGE data highlights the transcriptional start sites (TSSs) and their usage at a single nucleotide resolution.
By coupling laser capture microdissection to nanoCAGE technology and next-generation sequencing we have identified the genome-wide collection of active promoters in the mouse Main Olfactory Epithelium (MOE). Transcription start sites (TSSs) for the large majority of Olfactory Receptors (ORs) have been previously mapped increasing our understanding of their promoter architecture. Here we show that in our nanoCAGE libraries of the mouse MOE we detect a large number of tags mapped in loci hosting Type-1 and Type-2 Vomeronasal Receptors genes (V1Rs and V2Rs). These loci also show a massive expression of Long Interspersed Nuclear Elements (LINEs). We have validated the expression of selected receptors detected by nanoCAGE with in situ hybridization, RT-PCR and qRT-PCR. This work extends the repertory of receptors capable of sensing chemical signals in the MOE, suggesting intriguing interplays between MOE and VNO for pheromone processing and positioning transcribed LINEs as candidate regulatory RNAs for VRs expression.
The development of next-generation sequences has brought not only high-throughput sequencing but also new possibilities for various kinds of analysis methods of genetic information. Dr. Hayashizaki et al. developed new technologies to construct the full-length cDNA library and applied them to high-throughput sequencing technologies for large-scale transcriptome analysis. These analysis results overturned the conventional assumption the 2% of the genome is transcribed by showing that 70% or more of the genome is transcribed as RNA through FANTOM activities which was founded in 2000 on their initiative. Further, the existence of 23,000 non-protein coding RNAs was confirmed. These new findings redefine the central dogma into a new picture containing new interaction cascade and the unexpected complexity of combined omics. The neo central dogma shows that there are three types of final products derived from genes; long ncRNA, small ncRNA, and protein. They play essential roles by forming complexes with each other to maintain life. Long ncRNA and small ncRNA play a role as a ligand with sequence information. Long ncRNA and protein play a role as a functional molecule. Here, I would like to introduce the neo central dogma concept and some of the mechanisms of ncRNAs.
For advancing personalized medicine, it is important to incorporate pharmacogenomics data into routine clinical practice. The SmartAmp method enables us to detect genetic polymorphisms or mutations in target genes within 30-40 min without DNA isolation and PCR amplification. The SmartAmp method has been developed based on the concept that DNA amplification per se is the signal for the presence of a specific target sequence. Differing from the widely used PCR, the SmartAmp reaction is an isothermal DNA amplification, where the initial step of copying a target sequence from the template DNA is critically important. For clinical applications, we have created SmartAmp primers and clinical device that detect genetic polymorphisms of human genes involved in drug-induced toxicity or disease risk. This chapter addresses both the basic molecular mechanism underlying the SmartAmp method and its practical applications to detect clinically important single nucleotide polymorphisms (SNPs).
Changes in environmental conditions lead to expression variation that manifest at the level of gene regulatory networks. Despite a strong understanding of the role noise plays in synthetic biological systems, it remains unclear how propagation of expression heterogeneity in an endogenous regulatory network is distributed and utilized by cells transitioning through a key developmental event.
Analyzing the RNA pool or transcription start sites requires effective means to convert RNA into cDNA libraries for digital expression counting. With current high-speed sequencers, it is necessary to flank the cDNAs with specific adapters. Adding template-switching oligonucleotides to reverse transcription reactions is the most commonly used approach when working with very small quantities of RNA even from single cells.
High-throughput techniques have identified numerous antisense (AS) transcripts and long non-coding RNAs (ncRNAs). However, their significance in cancer biology remains largely unknown. Here, we report an androgen-responsive long ncRNA, CTBP1-AS, located in the AS region of C-terminal binding protein 1 (CTBP1), which is a corepressor for androgen receptor. CTBP1-AS is predominantly localized in the nucleus and its expression is generally upregulated in prostate cancer. CTBP1-AS promotes both hormone-dependent and castration-resistant tumour growth. Mechanistically, CTBP1-AS directly represses CTBP1 expression by recruiting the RNA-binding transcriptional repressor PSF together with histone deacetylases. CTBP1-AS also exhibits global androgen-dependent functions by inhibiting tumour-suppressor genes via the PSF-dependent mechanism thus promoting cell cycle progression. Our findings provide new insights into the functions of ncRNAs that directly contribute to prostate cancer progression.
Endogenous siRNAs (endo-siRNAs) are key regulators of RNA silencing in plants and worms; however, the biogenesis and function of endogenous siRNAs in mammals remain largely unknown. We previously demonstrated that human telomerase reverse transcriptase produces a self-targeting endogenous siRNA from non-coding RMRP RNA via RNA-dependent RNA polymerase (RdRP) activity. Here, we investigated whether the endo-siRNA derived from RMRP targets other genes in addition to RMRP. Four algorithms for microRNA target prediction were used to identify possible targets of the endo-siRNA, and the phytanoyl-CoA hydroxylase-interacting protein-like gene (PHYHIPL) was identified as the most promising candidate. The 3 UTR of PHYHIPL was found to contain three possible target sites with perfect seed pairing; deletion of each of these sites resulted in recovery of upstream luciferase expression. In addition, sequence-specific inhibition of the RMRP-derived endo-siRNA increased expression of PHYHIPL mRNA. The results described here suggest that the endo-siRNA uses silencing mechanisms that are similar to those used by microRNAs for gene silencing. To our knowledge, this study is the first confirmation of the off-target effect of human endogenous siRNA produced by RdRP activity.
Organic anion-transporting polypeptide (OATP) 1B1, encoded by the solute carrier organic anion transporter family member 1B1 (SLCO1B1) gene, mediates the active uptake of various organic anions into hepatocytes and determines their hepatic clearances as the first step in the detoxification pathway. Previous reports indicated that alterations in its function by drug-drug interactions or genetic polymorphisms affect the pharmacokinetics of the substrate drugs. In the present study, we developed a method to genotype SLCO1B1 388A>G (rs2306283) and 521>C (rs4149056), which significantly affect the clinical pharmacokinetics and subsequent side effects such as myopathy caused by statins, OATP1B1 substrates in humans. We used a small aliquot of blood and the isothermal Smart Amplification Process version 2 (SmartAmp-2), which could complete the genotyping of 388A>G and 521T>C within 60 min. The genotypes of 101 genomic DNA samples and blood samples assessed by SmartAmp-2 matched perfectly to those determined previously by the conventional PCR-SSCP method. The SmartAmp-2 method enables the rapid identification of the 388A>G and 521T>C genotypes, saving time and effort in the genomic DNA preparation in clinical practice. This method will be useful for evaluating and predicting altered pharmacological and toxicological effects of substrate drugs caused by SLCO1B1 polymorphisms.
Genetic polymorphisms in the human MDM2 gene are suggested to be a tumor susceptibility marker and a prognostic factor for cancer. It has been reported that a single nucleotide polymorphism (SNP) c.309T>G in the MDM2 gene attenuates the tumor suppressor activity of p53 and accelerates tumor formation in humans.
PROM1 is the gene encoding prominin-1 or CD133, an important cell surface marker for the isolation of both normal and cancer stem cells. PROM1 transcripts initiate at a range of transcription start sites (TSS) associated with distinct tissue and cancer expression profiles. Using high resolution Cap Analysis of Gene Expression (CAGE) sequencing we characterize TSS utilization across a broad range of normal and developmental tissues. We identify a novel proximal promoter (P6) within CD133(+) melanoma cell lines and stem cells. Additional exon array sampling finds P6 to be active in populations enriched for mesenchyme, neural stem cells and within CD133(+) enriched Ewing sarcomas. The P6 promoter is enriched with respect to previously characterized PROM1 promoters for a HMGI/Y (HMGA1) family transcription factor binding site motif and exhibits different epigenetic modifications relative to the canonical promoter region of PROM1.
The transcription factor NRF2 plays a pivotal role in protecting normal cells from external toxic challenges and oxidative stress, whereas it can also endow cancer cells resistance to anticancer drugs. At present little information is available about the genetic polymorphisms of the NRF2 gene and their clinical relevance. We aimed to investigate the single nucleotide polymorphisms in the NRF2 gene as a prognostic biomarker in lung cancer.
Real-time monitoring of PCR is one of the most important methods for DNA and RNA detection widely used in research and medical diagnostics. Here we describe a new approach for combined real-time PCR monitoring and melting curve analysis using a 3 end-blocked Exciton-Controlled Hybridization-sensitive fluorescent Oligonucleotide (ECHO) called Eprobe. Eprobes contain two dye moieties attached to the same nucleotide and their fluorescent signal is strongly suppressed as single-stranded oligonucleotides by an excitonic interaction between the dyes. Upon hybridization to a complementary DNA strand, the dyes are separated and intercalate into the double-strand leading to strong fluorescence signals. Intercalation of dyes can further stabilize the DNA/DNA hybrid and increase the melting temperature compared to standard DNA oligonucleotides. Eprobes allow for specific real-time monitoring of amplification reactions by hybridizing to the amplicon in a sequence-dependent manner. Similarly, Eprobes allow for analysis of reaction products by melting curve analysis. The function of different Eprobes was studied using the L858R mutation in the human epidermal growth factor receptor (EGFR) gene, and multiplex detection was demonstrated for the human EGFR and KRAS genes using Eprobes with two different dyes. Combining amplification and melting curve analysis in a single-tube reaction provides powerful means for new mutation detection assays. Functioning as "sequence-specific dyes", Eprobes hold great promises for future applications not only in PCR but also as hybridization probes in other applications.
Odorous chemicals are detected by the mouse main olfactory epithelium (MOE) by about 1100 types of olfactory receptors (OR) expressed by olfactory sensory neurons (OSNs). Each mature OSN is thought to express only one allele of a single OR gene. Major impediments to understand the transcriptional control of OR gene expression are the lack of a proper characterization of OR transcription start sites (TSSs) and promoters, and of regulatory transcripts at OR loci. We have applied the nanoCAGE technology to profile the transcriptome and the active promoters in the MOE. nanoCAGE analysis revealed the map and architecture of promoters for 87.5% of the mouse OR genes, as well as the expression of many novel noncoding RNAs including antisense transcripts. We identified candidate transcription factors for OR gene expression and among them confirmed by chromatin immunoprecipitation the binding of TBP, EBF1 (OLF1), and MEF2A to OR promoters. Finally, we showed that a short genomic fragment flanking the major TSS of the OR gene Olfr160 (M72) can drive OSN-specific expression in transgenic mice.
Recent research hints at an underappreciated complexity in pre-miRNA processing and regulation. Global profiling of pre-miRNA and its potential to increase understanding of the pre-miRNA landscape is impeded by overlap with highly expressed classes of other non coding (nc) RNA. Here, we present a data set excluding these RNA before sequencing through locked nucleic acids (LNA), greatly increasing pre-miRNA sequence counts with no discernable effect on pre-miRNA or mature miRNA sequencing. Analysis of profiles generated in total, nuclear and cytoplasmic cell fractions reveals that pre-miRNAs are subject to a wide range of regulatory processes involving loci-specific 3- and 5-end variation entailing complex cleavage patterns with co-occurring polyuridylation. Additionally, examination of nuclear-enriched flanking sequences of pre-miRNA, particularly those derived from polycistronic miRNA transcripts, provides insight into miRNA and miRNA-offset (moRNA) production, specifically identifying novel classes of RNA potentially functioning as moRNA precursors. Our findings point to particularly intricate regulation of the let-7 family in many ways reminiscent of DICER1-independent, pre-mir-451-like processing, introduce novel and unify known forms of pre-miRNA regulation and processing, and shed new light on overlooked products of miRNA processing pathways.
?2 and ?3 adrenergic receptors (?2AR, ?3AR) and uncoupling protein 1 (UCP1) have been considered as candidate genes for obesity. Although each polymorphism of ?3AR Trp64Arg, ?2AR Arg16Gly and UCP1 -3826A>G is known to be associated with obesity, the interaction among these polymorphisms is not fully understood. We analyzed ?3AR Trp64Arg, ?2AR Arg16Gly and UCP1 -3826A>G polymorphisms by the Smart Amplification Process 2 in 222 Japanese subjects without the medication of hypertension, dyslipidemia or diabetes, and investigated the association between the physical and metabolic characteristics and the combination of these polymorphisms. In analysis of the genotypes combination, only the carriers of both ?2AR Arg/Arg and UCP1 G/G genotypes had significantly higher waist to hip ratio (p=0.014). In analysis of the alleles combination, a significant difference was observed in waist to hip ratio among the groups stratified by the carrying number of the alleles of ?3AR Arg, ?2AR Arg and UCP1 G (p=0.026), and the waist to hip ratio was significantly higher in the carriers of four and five risk alleles than in the carriers from zero to three risk alleles (p=0.005). The present study demonstrated the interaction among ?3AR Trp64Arg, ?2AR Arg16Gly and UCP1 -3826A>G for the accumulation of visceral fat.
Restriction landmark genome scanning (RLGS) method is a high-resolution two-dimensional electrophoresis system for analyses of the whole genome DNA which is including methylation status. It has been used for cloning genes of model animals and human genomes, detection of imprinted genes, and genome-wide methylation research in cancer. The conventional RLGS detected both polymorphism and methylated NotI sites between samples. Here, we have developed improved RLGS method with isoschizomer restriction enzymes such as MspI and HpaII to specifically detect methylated sites, using differential sensitivity of the restriction enzymes to methylated sequences. Recently, by using the genome database information, the RLGS spot sites were efficiently identified by this improved method. Then, genome methylation sites of Arabidopsis were mapped, and a unique inheritance was detected in methylated gene in rice. Now, epigenetic research becomes easy with the improved RLGS and it also can be applied for animal genome. Therefore, RLGS method is useful to explore for novel epigenetic phenomenon.
The International Human Genome Sequencing Consortium completed the decoding of the human genome sequence in 2003. Readers will be aware of the paradigm shift which has occurred since then in the field of life science research. At last, mankind has been able to focus on a complete picture of the full extent of the genome, on which is recorded the basic information that controls all life. Meanwhile, another genome project, centered on Japan and known as the mouse genome encyclopedia project, was progressing with participation from around the world. Led by our research group at RIKEN, it was a full-length cDNA project which aimed to decode the whole RNA (transcriptome) using the mouse as a model. The basic information that controls all life is recorded on the genome, but in order to obtain a complete picture of this extensive information, the decoding of the genome alone is far from sufficient. These two genome projects established that the number of letters in the genome, which is the blueprint of life, is finite, that the number of RNA molecules derived from it is also finite, and that the number of protein molecules derived from the RNA is probably finite too. A massive number of combinations is still involved, but we are now able to understand one section of the network formed by these data. Once an object of study has been understood to be finite, establishing an image of the whole is certain to lead us to an understanding of the whole. Omics is an approach that views the information controlling life as finite and seeks to assemble and analyze it as a whole. Here, I would like to present our transcriptome research while making reference to our unique research strategy.
Genetic polymorphisms and mutations in drug metabolizing enzymes, transporters, receptors, and other drug targets (e.g., toxicity targets) are linked to inter-individual differences in the efficacy and toxicity of many medications as well as risk of genetic diseases. Validation of clinically important genetic polymorphisms and the development of new technologies to rapidly detect clinically important variants are critical issues for advancing personalized medicine. A key requirement for the advancing personalized medicine resides in the ability of rapidly and conveniently testing patients genetic polymorphisms and/or mutations. We have recently developed a rapid and cost-effective method, named Smart Amplification Process 2 (SmartAmp2), which enables us to detect genetic polymorphisms or mutations in target genes within 30 to 45 min under isothermal conditions without DNA isolation and PCR amplification. Detection of mutations or single nucleotide polymorphisms (SNPs) in human ABC transporter genes is becoming more important, since their functional impairments are reportedly associated with inherited diseases. Thus, certain genetic polymorphisms of ABC transporters are considered important biomarkers for diagnosis of inherited diseases and/or risk of drug-induced adverse reactions. In this review article, we will present the new technology of the SmartAmp2 method and its clinical applications for detection of SNPs in human ABC transporter genes, i.e., ABCC4 and ABCC11.
Mesothelioma is a highly malignant tumor that is primarily caused by occupational or environmental exposure to asbestos fibers. Despite worldwide restrictions on asbestos usage, further cases are expected as diagnosis is typically 20-40 years after exposure. Once diagnosed there is a very poor prognosis with a median survival rate of 9 months. Considering this the development of early pre clinical diagnostic markers may help improve clinical outcomes.
The pluripotency of mouse embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) can be maintained by feeder cells, which secrete leukemia inhibitory factor (LIF). We found that feeder cells provide a relatively low concentration (25 unit/ml) of LIF, which is insufficient to maintain the ESCs/iPSCs pluripotency in feeder free conditions. To identify additional factors involved in the maintenance of pluripotency, we carried out a global transcript expression profiling of mouse iPSCs cultured on feeder cells and in feeder-free (LIF-treated) conditions. This identified 17 significantly differentially expressed genes (adjusted p value <0.05) including seven chemokines overexpressed in iPSCs grown on feeder cells. Ectopic expression of these chemokines in iPSCs revealed that CC chemokine ligand 2 (Ccl2) induced the key transcription factor genes for pluripotency, Klf4, Nanog, Sox2, and Tbx3. Furthermore, addition of recombinant Ccl2 protein drastically increased the number of Nanog-green fluorescent protein-positive iPSCs grown in low-LIF feeder free conditions. We further revealed that pluripotency promotion by Ccl2 is mediated by activating the Stat3-pathway followed by Klf4 upregulation. We demonstrated that Ccl2-mediated increased pluripotency is independent of phosphoinositide 3-kinase and mitogen-activated protein kinase pathways and that Tbx3 may be upregulated by Klf4. Overall, Ccl2 cooperatively activates the Stat3-pathway with LIF in feeder-free conditions to maintain pluripotency for ESCs/iPSCs.
Taste buds contain three types of taste cells. Each type can respond to taste stimulation, and type II and III taste cells are electrically excitable. However, there are differences between the properties of type II and III taste cells. In this study, we found that Fxyd6, an Na,K-ATPase regulator gene, is expressed in type II taste cells in the taste buds of mice. Double-labeled in situ hybridization analysis showed that Fxyd6 was coexpressed with transient receptor potential cation channel, subfamily M, member 5 (Trpm5), a critical component of the sweet, bitter, and umami taste signal transduction pathways and that it was specifically expressed in type II taste cells. We also found that taste cells frequently coexpressed Fxyd6 and Na,K-ATPase ?1. These results indicate the presence of an inherent mechanism that regulated transmembrane Na(+) dynamics in type II taste cells.
We report the development of a simplified cap analysis of gene expression (CAGE) protocol adapted for single-molecule sequencers that avoids second strand synthesis, ligation, digestion, and PCR. HeliScopeCAGE directly sequences the 3 end of cap trapped first-strand cDNAs. As with previous versions of CAGE, we better define transcription start sites (TSS) than known models, identify novel regions of transcription and alternative promoters, and find two major classes of TSS signal, sharp peaks and broad regions. However, using this protocol, we observe reproducible evidence of regulation at the much finer level of individual TSS positions. The libraries are quantitative over 5 orders of magnitude and highly reproducible (Pearsons correlation coefficient of 0.987). We have also scaled down the sample requirement to 5 ?g of total RNA for a standard HeliScopeCAGE library and 100 ng for a low-quantity version. When the same RNA was run as 5-?g and 100-ng versions, the 100 ng was still able to detect expression for ?60% of the 13,468 loci detected by a 5-?g library using the same threshold, allowing comparative analysis of even rare cell populations. Testing the protocol for differential gene expression measurements on triplicate HeLa and THP-1 samples, we find that the log fold change compared to Illumina microarray measurements is highly correlated (0.871). In addition, HeliScopeCAGE finds differential expression for thousands more loci including those with probes on the array. Finally, although the majority of tags are 5 associated, we also observe a low level of signal on exons that is useful for defining gene structures.
The pathway for RNA interference is widespread in metazoans and participates in numerous cellular tasks, from gene silencing to chromatin remodeling and protection against retrotransposition. The unicellular eukaryote Trypanosoma cruzi is missing the canonical RNAi pathway and is unable to induce RNAi-related processes. To further understand alternative RNA pathways operating in this organism, we have performed deep sequencing and genome-wide analyses of a size-fractioned cDNA library (16-61 nt) from the epimastigote life stage. Deep sequencing generated 582,243 short sequences of which 91% could be aligned with the genome sequence. About 95-98% of the aligned data (depending on the haplotype) corresponded to small RNAs derived from tRNAs, rRNAs, snRNAs and snoRNAs. The largest class consisted of tRNA-derived small RNAs which primarily originated from the 3 end of tRNAs, followed by small RNAs derived from rRNA. The remaining sequences revealed the presence of 92 novel transcribed loci, of which 79 did not show homology to known RNA classes.
Human DICER1 protein cleaves double-stranded RNA into small sizes, a crucial step in production of single-stranded RNAs which are mediating factors of cytoplasmic RNA interference. Here, we clearly demonstrate that human DICER1 protein localizes not only to the cytoplasm but also to the nucleoplasm. We also find that human DICER1 protein associates with the NUP153 protein, one component of the nuclear pore complex. This association is detected predominantly in the cytoplasm but is also clearly distinguishable at the nuclear periphery. Additional characterization of the NUP153-DICER1 association suggests NUP153 plays a crucial role in the nuclear localization of the DICER1 protein.
The presence of EGFR mutations is correlated with a positive therapeutic response to tyrosine kinase inhibitors; therefore, the accurate detection of EGFR mutations is crucial when deciding appropriate therapeutic strategies. Recently, the rapid and sensitive assay smart amplification process version 2 (SmartAmp2) was developed. However, this method can only detect one type of mutation in EGFR exon 19; therefore, we applied the PNA technology to the SmartAmp2 assay to develop PNA-clamp SmartAmp2 for the detection of many types of deletions in EGFR exon 19, in a single reaction. This new assay was evaluated using 172 clinical samples. Thirty-nine (22.7%) samples were found to have deletions by PNA-clamp SmartAmp2; whereas 30 (17.4%) and 38 (22.1%) tumors were found to have deletions by direct sequencing and PNA-enriched sequencing, respectively. Three cases, in which we detected mutations with PNA-clamp SmartAmp2, but not with direct sequencing, were treated with gefitinib, and all cases showed a partial therapeutic response. Using clinical samples, we demonstrated that PNA-clamp SmartAmp2 can detect various types of mutations in EGFR exon 19 in a relatively short time and with high sensitivity. This method detected small amounts of mutant DNA and identified patients for whom clinical information was previously unavailable from other tests. This test may contribute to the administration of efficient therapeutic strategies.
Pandemic influenza A(H1N1) virus infection quickly circulated worldwide in 2009. In Japan, the first case was reported in May 2009, one month after its outbreak in Mexico. Thereafter, A(H1N1) infection spread widely throughout the country. It is of great importance to profile and understand the situation regarding viral mutations and their circulation in Japan to accumulate a knowledge base and to prepare clinical response platforms before a second pandemic (pdm) wave emerges.
Genetic polymorphisms of the human CYP2A6 gene are considered to be a determinant of smoking behavior and tobacco-related lung cancer risk in male Japanese smokers. We developed a SmartAmp-based genotyping method to detect whole deletion of the CYP2A6 gene directly from blood samples without DNA isolation.
The cap analysis of gene expression (CAGE) technology has been established to detect transcriptional starting sites (TSSs) and expression levels by utilizing 5 cDNA tags and PCR. It has been reported that the amount of templates is proportional to the amplification efficiency of PCR. CAGE has been used as a key technique for analyzing promoter activity and finding new transcripts including alternative spliced products and noncoding transcripts. Here, we introduce more powerful tools such as deepCAGE, which can be utilized for high-throughput next-generation sequencing technology. DeepCAGE can produce much deeper transcriptome datasets and can reveal more details of the regulatory network.
The application of isothermal amplification technologies is rapidly expanding and currently covers different areas such as infectious disease, genetic disorder and drug dosage adjustment. Meanwhile, many of such technologies have complex reaction processes and often require a fine-tuned primer set where existing primer design tools are not sufficient. We have developed a primer selection system for one important primer, the turn-back primer (TP), which is commonly used in loop-mediated amplification (LAMP) and smart amplification process (SmartAmp). We chose 78 parameters related to the primer and target sequence, and explored their relationship to amplification speed using experimental data for 1344 primer combinations. We employed the least absolute shrinkage and selection operator (LASSO) method for parameter selection and estimation of their numerical coefficients. We subsequently evaluated our prediction model using additional independent experiments and compared to the LAMP primer design tool, Primer Explorer version4 (PE4). The evaluation showed that our approach yields a superior primer design in isothermal amplification and is robust against variations in the experimental setup. Our LASSO regression analysis revealed that availability of the 3- and 5-end of the primer are particularly important factors for efficient isothermal amplification. Our computer script is freely available at: http://gerg.gsc.riken.jp/TP_optimization/.
DICER is an RNase III family endoribonuclease that processes precursor microRNAs (pre-miRNAs) and long double-stranded RNAs, generating microRNA (miRNA) duplexes and short interfering RNA duplexes with 20~23 nucleotides (nts) in length. The typical form of pre-miRNA processed by the Drosha protein is a hairpin RNA with 2-nt 3 overhangs. On the other hand, production of mature miRNA from an endogenous hairpin RNA with 5 overhangs has also been reported, although the mechanism for this process is unknown.
While several studies have focused on the relationship between individual miRNA loci or classes of small RNA with human Argonaute (AGO) proteins, a comprehensive, global analysis of the RNA content associating with different AGO proteins has yet to be performed. We have compared the content of deep sequenced RNA extracted from immunoprecipitation experiments with the AGO1, AGO2, and AGO3 proteins. Consistent with previous observations, sequence tags derived from miRNA loci globally associate in approximately equivalent amounts with AGO1, AGO2, and AGO3. Exceptions include miR-182, miR-222, and miR-223*, which could be coupled to processes targeting the loci for interaction with specific AGO proteins. A closer inspection of the data, however, supports the presence of an unusual sorting mechanism wherein a subset of miRNA loci give rise to distinct isomirs which preferentially associate with distinct AGO proteins in a significantly differential manner. We also identify the complete set of short RNA derived from non-miRNA sources including tRNA, snRNA, snoRNA, vRNA, and mRNA associating with the AGO proteins, many of which are predicted to play roles in post-transcriptional gene silencing. We also observe enrichment of tags mapping to promoter regions of genes, suggesting that a fraction of the recently-identified promoter-associated small RNAs in humans could function through interaction with AGO proteins. Finally, we observe antisense miRNA transcripts are frequently present in low copy numbers across a range of diverse miRNA loci and these transcripts appear to associate with AGO proteins.
International mortality and frequency rates for breast cancer have been associated with the wet type of human earwax. It was recently found that earwax type is determined by a single nucleotide polymorphism (SNP), 538G>A (Gly180Arg), in ABCC11. The G allele determines the wet type of earwax as a Mendelian trait with a dominant phenotype. The present study examined the association between the frequency rate of breast cancer and the frequency of the G allele of ABCC11.
In DNA amplification, the initial step of copying a target sequence from the template DNA--the so-called intermediate product generation step--is very important. In examining the turn-back primer (TP)-dependent isothermal DNA amplification (TIA) method, we determined the actual time point of intermediate product generation by extrapolating dsDNA amplification curves. Our results indicate that intermediate product creation is the rate-limiting step in TIA, and good TP design is advantageous for improving the intermediate production process.
The sequence alignment/map format (SAM) is a commonly used format to store the alignments between millions of short reads and a reference genome. Often certain positions within the reads are inherently more likely to contain errors due to the protocols used to prepare the samples. Such biases can have adverse effects on both mapping rate and accuracy. To understand the relationship between potential protocol biases and poor mapping we wrote SAMstat, a simple C program plotting nucleotide overrepresentation and other statistics in mapped and unmapped reads in a concise html page. Collecting such statistics also makes it easy to highlight problems in the data processing and enables non-experts to track data quality over time.
The RIKEN integrated database of mammals (http://scinets.org/db/mammal) is the official undertaking to integrate its mammalian databases produced from multiple large-scale programs that have been promoted by the institute. The database integrates not only RIKENs original databases, such as FANTOM, the ENU mutagenesis program, the RIKEN Cerebellar Development Transcriptome Database and the Bioresource Database, but also imported data from public databases, such as Ensembl, MGI and biomedical ontologies. Our integrated database has been implemented on the infrastructure of publication medium for databases, termed SciNetS/SciNeS, or the Scientists Networking System, where the data and metadata are structured as a semantic web and are downloadable in various standardized formats. The top-level ontology-based implementation of mammal-related data directly integrates the representative knowledge and individual data records in existing databases to ensure advanced cross-database searches and reduced unevenness of the data management operations. Through the development of this database, we propose a novel methodology for the development of standardized comprehensive management of heterogeneous data sets in multiple databases to improve the sustainability, accessibility, utility and publicity of the data of biomedical information.
The international Functional Annotation Of the Mammalian Genomes 4 (FANTOM4) research collaboration set out to better understand the transcriptional network that regulates macrophage differentiation and to uncover novel components of the transcriptome employing a series of high-throughput experiments. The primary and unique technique is cap analysis of gene expression (CAGE), sequencing mRNA 5-ends with a second-generation sequencer to quantify promoter activities even in the absence of gene annotation. Additional genome-wide experiments complement the setup including short RNA sequencing, microarray gene expression profiling on large-scale perturbation experiments and ChIP-chip for epigenetic marks and transcription factors. All the experiments are performed in a differentiation time course of the THP-1 human leukemic cell line. Furthermore, we performed a large-scale mammalian two-hybrid (M2H) assay between transcription factors and monitored their expression profile across human and mouse tissues with qRT-PCR to address combinatorial effects of regulation by transcription factors. These interdependent data have been analyzed individually and in combination with each other and are published in related but distinct papers. We provide all data together with systematic annotation in an integrated view as resource for the scientific community (http://fantom.gsc.riken.jp/4/). Additionally, we assembled a rich set of derived analysis results including published predicted and validated regulatory interactions. Here we introduce the resource and its update after the initial release.
Here we describe a method for constructing small RNA libraries for high-throughput sequencing in which we have made a significant improvement to commonly available standard protocols. We added a locked nucleic acid (LNA) oligonucleotide--named dimer eliminator--that is complementary to the adapter-dimer ligation products during the reverse transcription reaction. It reduces adapter-dimers, which often contaminate standard libraries and increase the number of non-insert sequence reads. This simple technology can be used for simultaneous multiplex sequencing of various barcoded samples as well as nonbarcoded small RNA library sequencing. In this study we also evaluated the reproducibility and quantitative design of the eight barcoded tags by comparing the Pearsons correlation values in the expression analysis between each barcoded sample. This method improves the sequencing yield and efficiency, while simplifying library construction, and makes it easier to perform large-scale small RNA analysis under multiple conditions with next-generation sequencers.
Perturbation and time-course data sets, in combination with computational approaches, can be used to infer transcriptional regulatory networks which ultimately govern the developmental pathways and responses of cells. Here, we individually knocked down the four transcription factors PU.1, IRF8, MYB and SP1 in the human monocyte leukemia THP-1 cell line and profiled the genome-wide transcriptional response of individual transcription starting sites using deep sequencing based Cap Analysis of Gene Expression. From the proximal promoter regions of the responding transcription starting sites, we derived de novo binding-site motifs, characterized their biological function and constructed a network. We found a previously described composite motif for PU.1 and IRF8 that explains the overlapping set of transcriptional responses upon knockdown of either factor.
Animal microRNA sequences are subject to 3 nucleotide addition. Through detailed analysis of deep-sequenced short RNA data sets, we show adenylation and uridylation of miRNA is globally present and conserved across Drosophila and vertebrates. To better understand 3 adenylation function, we deep-sequenced RNA after knockdown of nucleotidyltransferase enzymes. The PAPD4 nucleotidyltransferase adenylates a wide range of miRNA loci, but adenylation does not appear to affect miRNA stability on a genome-wide scale. Adenine addition appears to reduce effectiveness of miRNA targeting of mRNA transcripts while deep-sequencing of RNA bound to immunoprecipitated Argonaute (AGO) subfamily proteins EIF2C1-EIF2C3 revealed substantial reduction of adenine addition in miRNA associated with EIF2C2 and EIF2C3. Our findings show 3 addition events are widespread and conserved across animals, PAPD4 is a primary miRNA adenylating enzyme, and suggest a role for 3 adenine addition in modulating miRNA effectiveness, possibly through interfering with incorporation into the RNA-induced silencing complex (RISC), a regulatory role that would complement the role of miRNA uridylation in blocking DICER1 uptake.
Clinical studies have suggested that a defect in both glutathione S-transferase (GST) M1 and GSTT1 increases the risk of drug-induced hepatotoxicity. The present study developed the method that enables genotyping of GSTM1 and GSTT1 directly using a small aliquot of blood samples based on an isothermal Smart amplification process version 2 (SmartAmp-2). SmartAmp-2 reaction could complete the genotyping of GSTM1 and GSTT1 within 40 min. The frequency of wild-type, GSTM1 null, GSTT1 null, and double null was 24, 21, 35, and 19%, respectively, consistent with previous reports in the Japanese population. The genotypes of 94 human genomic DNA samples determined by SmartAmp-2 were identical to those determined by the conventional polymerase chain reaction method. SmartAmp-2 was able to determine the genotypes of GSTM1 and GSTT1 even when human blood specimens were used. The SmartAmp-2 method is a rapid and accurate means of identifying the GSTM1 and GSTT1 genotypes, making it less time and more labor efficient in clinical practice than conventional methods requiring preparation of genomic DNA and electrophoresis. This will contribute to evaluate the susceptibility of disease and adverse reactions to drugs caused by deletion of GSTM1 and GSTT1.
Although transcription in mammalian genomes can initiate from various genomic positions (e.g., 3UTR, coding exons, etc.), most locations on genomes are not prone to transcription initiation. It is of practical and theoretical interest to be able to estimate such collections of non-TSS locations (NTLs). The identification of large portions of NTLs can contribute to better focusing the search for TSS locations and thus contribute to promoter and gene finding. It can help in the assessment of 5 completeness of expressed sequences, contribute to more successful experimental designs, as well as more accurate gene annotation.
Several technologies are currently used for gene expression profiling, such as Real Time RT-PCR, microarray and CAGE (Cap Analysis of Gene Expression). CAGE is a recently developed method for constructing transcriptome maps and it has been successfully applied to analyzing gene expressions in diverse biological studies. The principle of CAGE has been developed to address specific issues such as determination of transcriptional starting sites, the study of promoter regions and identification of new transcripts. Here, we present both quantitative and qualitative comparisons among three major gene expression quantification techniques, namely: CAGE, illumina microarray and Real Time RT-PCR, by showing that the quantitative values of each method are not interchangeable, however, each of them has unique characteristics which render all of them essential and complementary. Understanding the advantages and disadvantages of each technology will be useful in selecting the most appropriate technique for a determined purpose.
Japanese flounder (Paralichthys olivaceus) is one of the most economically important marine species in Northeast Asia. Information on genetic markers associated with quantitative trait loci (QTL) can be used in breeding programs to identify and select individuals carrying desired traits. Commercial production of Japanese flounder could be increased by developing disease-resistant fish and improving commercially important traits. Previous maps have been constructed with AFLP markers and a limited number of microsatellite markers. In this study, improved genetic linkage maps are presented. In contrast with previous studies, these maps were built mainly with a large number of codominant markers so they can potentially be used to analyze different families and populations.
Large-scale sequencing projects have revealed an unexpected complexity in the origins, structures and functions of mammalian transcripts. Many loci are known to produce overlapping coding and noncoding RNAs with capped 5 ends that vary in size. Methods to identify the 5 ends of transcripts will facilitate the discovery of new promoters and 5 ends derived from secondary capping events. Such methods often require high input amounts of RNA not obtainable from highly refined samples such as tissue microdissections and subcellular fractions. Therefore, we developed nano-cap analysis of gene expression (nanoCAGE), a method that captures the 5 ends of transcripts from as little as 10 ng of total RNA, and CAGEscan, a mate-pair adaptation of nanoCAGE that captures the transcript 5 ends linked to a downstream region. Both of these methods allow further annotation-agnostic studies of the complex human transcriptome.
Histone modifications play an important role in gene regulation. Acetylation of histone 3 lysine 9 (H3K9ac) is generally associated with transcription initiation and unfolded chromatin, thereby positively influencing gene expression. Deep sequencing of the 5 ends of gene transcripts using DeepCAGE delivers detailed information about the architecture and expression level of gene promoters. The combination of H3K9ac ChIP-chip and DeepCAGE in a myeloid leukemia cell line (THP-1) allowed us to study the spatial distribution of H3K9ac around promoters using a novel clustering approach. The promoter classes were analyzed for association with relevant genomic sequence features.
Gene regulatory networks in living cells are controlled by the interaction of multiple cell type-specific transcription regulators with DNA binding sites in target genes. Interferon regulatory factor 8 (IRF8), also known as interferon consensus sequence binding protein (ICSBP), is a transcription factor expressed predominantly in myeloid and lymphoid cell lineages. To find the functional direct target genes of IRF8, the gene expression profiles of siRNA knockdown samples and genome-wide binding locations by ChIP-chip were analyzed in THP-1 myelomonocytic leukemia cells. Consequently, 84 genes were identified as functional direct targets. The ETS family transcription factor PU.1, also known as SPI1, binds to IRF8 and regulates basal transcription in macrophages. Using the same approach, we identified 53 direct target genes of PU.1; these overlapped with 19 IRF8 targets. These 19 genes included key molecules of IFN signaling such as OAS1 and IRF9, but excluded other IFN-related genes amongst the IRF8 functional direct target genes. We suggest that IRF8 and PU.1 can have both combined, and independent actions on different promoters in myeloid cells.
High mobility group box protein 1 (HMGB1), a major non-histone protein, released from the cells induces dendritic cell (DC) maturation and Th1 polarization. While DNA immunization has become an attractive method for eliciting the production of antibodies (Abs) in animals injected with DNA encoding an antigen, the Ab responses induced by DNA immunization remain relatively weak. In this study, we investigated the release of an HMGB1-conjugated ovalbumin (HMGB1 OVA conjugate, HMGB1-OVA) from necrotic cells and the Ab responses to HMGB1-OVA following DNA immunization. HMGB1-OVA was released from 293T cells after induction of necrosis in vitro and from the muscle into the serum after DNA immunization followed by electroporation. DCs pulsed with the supernatant of necrotic 293T cells containing HMGB1-OVA induced DO11.10 CD4+ T cell proliferation and interferon-? secretion more potently than DCs pulsed with the cell supernatant containing OVA. DNA immunization with an expression plasmid for HMGB1-OVA by intramuscular injection elicited enhanced Th1-type Ab responses to OVA. Moreover, DNA immunization with a plasmid vector for release-type HMGB1 mutant-conjugated OVA elicited an even stronger response than DNA immunization with wild-type HMGB1-OVA. HMGB1-based DNA immunization described here has the potential to enhance the immunogenicity of antigens and elicit stronger Th1-type Ab response.
We developed 90%-hepatectomized mice that were the fatal model, and analyzed the gene expression profiles using a complementary DNA (cDNA) microarray to clarify the mechanisms of hepatic failure after excessive hepatectomy.
Combinatorial interactions among transcription factors are critical to directing tissue-specific gene expression. To build a global atlas of these combinations, we have screened for physical interactions among the majority of human and mouse DNA-binding transcription factors (TFs). The complete networks contain 762 human and 877 mouse interactions. Analysis of the networks reveals that highly connected TFs are broadly expressed across tissues, and that roughly half of the measured interactions are conserved between mouse and human. The data highlight the importance of TF combinations for determining cell fate, and they lead to the identification of a SMAD3/FLI1 complex expressed during development of immunity. The availability of large TF combinatorial networks in both human and mouse will provide many opportunities to study gene regulation, tissue differentiation, and mammalian evolution.
DNA immunization or vaccination, which refers to the injection of DNA encoding the corresponding antigen proteins, has become an attractive method for inducing the production of antibodies (Abs) in animals, since it does not require proteins as antigens. However, a method for detecting Abs produced in response to antigens is still essential for the quantification of Abs in the sera of immunized animals and for the screening of monoclonal antibody (mAb)-producing hybridomas. Here, we report a new system for the evaluation of Abs against antigens that are difficult to purify, by employing intracellular biotinylation of the antigen protein. The antigen tagged with a peptide to be biotinylated (Bio-tag) and codon-optimized bacterial BirA biotin ligase were co-expressed in mammalian cells, and the biotinylated Bio-tagged antigen was captured on a streptavidin-coated plate. Abs against five human nuclear antigens that were difficult to purify as full-length recombinant proteins were detected in the sera of DNA-immunized mice, and IgG mAbs against three of these antigens were selected by ELISA. The results demonstrate that this system employing intracellular biotinylation of the antigen is a powerful technique for stimulating the production of Abs following DNA immunization.
Recent evidence indicates that the presence of epidermal growth factor receptor (EGFR) or KRAS mutations in non-small cell lung cancer (NSCLC) can predict the response of the tumor to gefinitib. However, it is difficult to detect these mutations using formalin-fixed, paraffin-embedded (FFPE) tissues because the fixation process and aging can damage the DNA. In this study, we describe our work in adapting the Smart Amplification Process version 2 (SmartAmp2) to detect EGFR or KRAS mutations in DNA extracted from FFPE tissues. We were able to detect these mutations in 37 (97%) of 38 FFPE lung cancer tissue samples within 60 minutes with the SmartAmp2 assay and to confirm the correlation between EGFR mutations in FFPE tissues and gefitinib responsiveness. All mutations had previously been confirmed in the 38 samples using DNA extracted from frozen tissues. Electrophoresis results indicated that PCR analysis was not reliable for DNA extracted from FFPE tissue when primers with a long amplicon (>300 bp) were used. This study confirms that the SmartAmp2 assay is suitable for use with DNA extracted from FFPE as well as frozen tissues.
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