Articles by Luis A. Ugozzoli In JoVE (2) باستخدام الجينات Electroporation MXcell بولسير النظام لTransfect الخلايا الأولية ذات الكفاءة العاليةباستخدام خلية مكافحة الآلي لتبسيط دراسات التعبير الجيني : ضربة قاضية سيرنا من IL - 4 التعبير الجيني في الخلايا التابعة Namalwa Other Publications (6) Analytical BiochemistryClinical ChemistryAnalytical BiochemistryMolecular and Cellular ProbesClinical ChemistryAnalytical Biochemistry Articles by Luis A. Ugozzoli in JoVE Biology باستخدام الجينات Electroporation MXcell بولسير النظام لTransfect الخلايا الأولية ذات الكفاءة العالية Adam M. McCoy1, Michelle L. Collins1, Luis A. Ugozzoli1 1Gene Expression Division, Bio-Rad Laboratories, Inc. هذا الإجراء يوضح كيفية استخدام الجينات electroporation MXcell بولسير النظام بسرعة وبسهولة تحديد أفضل الظروف لelectroporation الليفية الماوس الجنينية (MEFs) أو الخلايا الأولية الأخرى. وتناقش أيضا اعتبارات المشاكل المرتبطة في شريط الفيديو. Biology باستخدام خلية مكافحة الآلي لتبسيط دراسات التعبير الجيني : ضربة قاضية سيرنا من IL - 4 التعبير الجيني في الخلايا التابعة Namalwa Adam M. McCoy1, Claudia Litterst1, Michelle L. Collins1, Luis A. Ugozzoli1 1Gene Expression Division, Bio-Rad Laboratories يصف هذا الإجراء سير عمل سريعة وسهلة لإدخال سيرنا إلى الصعب transfect خطوط الخلايا والجينات التي تتبع في الوقت الحقيقي PCR. استخدام عداد الخلية الآلي ، وكذلك لوحة متعددة electroporation ، ومؤتمتة محطة الكهربائي تقديم نتائج سريعة وموثوق بها من دون الحاجة للتعامل مع آلية مكلفة. Other articles by Luis A. Ugozzoli on PubMed Fluorescent Multicolor Multiplex Homogeneous Assay for the Simultaneous Analysis of the Two Most Common Hemochromatosis Mutations Analytical Biochemistry. Aug, 2002 | Pubmed ID: 12137778 We report the development of a qualitative fluorescent multiplex homogeneous assay designed for the detection of the two most common hemochromatosis mutations using dual-labeled fluorescent probes. The assay is able to detect four allelic variants in a single closed tube using a single thermocycling protocol. The procedure combines the great sensitivity of the polymerase chain reaction, the specificity provided by allele-specific oligonucleotide hybridization using the 5(') nuclease assay format, and the higher throughput of a multicolor fluorescence detection procedure. Genomic DNA was prepared from whole blood specimens using standard procedures. Following DNA sample preparation, two regions of the hemochromatosis gene (HFE) including the H63D and C282Y mutations were coamplified and detected in real-time by four different fluorescently labeled allele-specific oligonucleotide probes. Assay specificity was demonstrated by a blind methods comparison study that included 37 DNA samples from individuals with a known HFE genotype. Results from the study showed that the multicolor multiplex HFE assay unambiguously classified all possible genotypes for the HFE gene C282Y and H63D mutations(1). This technique will be useful for research and molecular diagnostic laboratories and can be easily adapted for the detection of other single nucleotide polymorphisms. Linked Linear Amplification for Simultaneous Analysis of the Two Most Common Hemochromatosis Mutations Clinical Chemistry. Jul, 2003 | Pubmed ID: 12816900 Two mutations in HFE, G845A (amino acid substitution C282Y) and C187G (H63D), are associated with hereditary hemochromatosis. We developed and validated a novel method, linked linear amplification (LLA), for detection of these two mutations. Real-time Genotyping with Oligonucleotide Probes Containing Locked Nucleic Acids Analytical Biochemistry. Jan, 2004 | Pubmed ID: 14654057 Oligonucleotide probes containing locked nucleic acid (LNA) hybridize to complementary single-stranded target DNA sequences with an increased affinity compared to oligonucleotide DNA probes. As a consequence of the incorporation of LNA residues into the oligonucleotide sequence, the melting temperature of the oligonucleotide increases considerably, thus allowing the successful use of shorter LNA probes as allele-specific tools in genotyping assays. In this article, we report the use of probes containing LNA residues for the development of qualitative fluorescent multiplex assays for the detection of single nucleotide polymorphisms (SNPs) in real-time polymerase chain reaction using the 5'-nuclease detection assay. We developed two applications that show the improved specificity of LNA probes in assays for allelic discrimination. The first application is a four-color 5'-nuclease assay for the detection of SNPs for two of the most common genetic factors involved in thrombotic risk, factor V Leiden and prothrombin G20210A. The second application is a two-color assay for the specific detection of the A-to-T tranversion in codon 6 of the beta-globin gene, responsible for sickle cell anemia. Both real-time genotyping assays were evaluated by comparing the performance of our method to that of a reference method and in both cases, we found a 100% concordance. This approach will be useful for research and molecular diagnostic laboratories in situations in which the specificity provided by oligonucleotide DNA probes is insufficient to discriminate between two DNA sequences that differ by only one nucleotide. Four-color Multiplex 5' Nuclease Assay for the Simultaneous Detection of the Factor V Leiden and the Prothrombin G20210A Mutations Molecular and Cellular Probes. Jun, 2004 | Pubmed ID: 15135449 We developed a real-time multiplex four-color assay for the simultaneous detection of the factor V Leiden (FVL) and prothrombin (PT) G20210A mutations in one closed tube using a single thermocycling protocol. The assay combines the power of multiplex PCR with the specificity provided by allele-specific oligonucleotide (ASO) hybridization using the 5' nuclease assay format. Human genomic DNA is prepared from whole blood with standard procedures. A 97-bp DNA sequence of the coagulation factor V gene is co-amplified with a 111-bp DNA sequence of the coagulation factor II (PT) gene using four PCR primers. In addition, the reactions included four differentially labeled ASO probes for the specific detection of the different FVL/PT G20210A genotypes. To evaluate the assay's performance characteristics, we performed a comparison of two methods. We analyzed DNA samples from 52 individuals with known FVL/PT G20210A genotypes that were previously genotyped with an assay that combined PCR with the use of restriction fragment length polymorphisms. We found a 100% concordance between the results generated by both methodologies. We conclude that the four-color multiplex assay is specific and reproducible for the detection of the FVL/PT G20210A mutations, and it can be easily adapted for the detection of other SNPs. Multiplex Assays with Fluorescent Microbead Readout: a Powerful Tool for Mutation Detection Clinical Chemistry. Nov, 2004 | Pubmed ID: 15502076 Four-color Multiplex Reverse Transcription Polymerase Chain Reaction--overcoming Its Limitations Analytical Biochemistry. Sep, 2005 | Pubmed ID: 16039598 Quantitative reverse transcription polymerase chain reaction (qRT-PCR) conducted in real time is a powerful tool for measuring messenger RNA (mRNA) levels in biological samples. Multiplex PCR is defined as the simultaneous amplification of two or more DNA (cDNA) targets in a single reaction vessel and may be carried out only using uniquely labeled probes for each target. Up to four genes can be detected in a multiplex 5' nuclease assay when using the appropriate instrument and the right combination of fluorophores. One of the more important advantages of multiplexing is a reduced sample requirement, which is especially important when sample material is scarce. Additional benefits are saving time on reaction setup and lower cost compared to singleplex reactions. Although multiplexing has several advantages over singleplex qRT-PCR, limited work has been done to show its feasibility. Few publications on four-color multiplex qRT-PCR have been reported, and to our knowledge no work has been done to explore the assay's limitations. In this paper, we report the first in-depth analysis of a four-gene multiplex qRT-PCR. To achieve a better understanding of the potential limitations of the qRT-PCR assay, we used in vitro transcribed RNA derived from four human genes. To emulate gene expression experiments, we developed a model system in which the in vitro transcripts were spiked with plant total RNA. This model allowed us to develop an artificial system closely resembling differential gene expression levels varying up to a million fold. We identified a single "universal" reaction condition that enabled optimal amplification in real time of up to four genes over a wide range of template concentrations. This study shows that multiplexing is a feasible approach applicable to most qRT-PCR assays performed with total RNA, independent of the expression levels of the genes under scrutiny.
