Years of research indicates that ovarian cancers harbor a heterogeneous mixture of cells including a subpopulation of so-called “cancer stem cells” (CSCs) responsible for tumor initiation, maintenance and relapse following conventional chemotherapies. Identification of ovarian CSCs is therefore an important goal. A commonly used method to assess CSC potential in vitro is the spheres assay in which cells are plated under non-adherent culture conditions in serum-free medium supplemented with growth factors and sphere formation is scored after a few days. Here, we review currently available protocols for human ovarian cancer spheres assays and perform a side-by-side analysis between commonly used multi cell-based assays and a more accurate system based on single cell plating. Our results indicate that both multi cell-based as well as single cell-based spheres assays can be used to investigate sphere formation in vitro. The more laborious and expensive single cell-based assays are more suitable for functional assessment of individual cells and lead to overall more accurate results while multi cell-based assays can be strongly influenced by the density of plated cells and require titration experiments upfront. Methylcellulose supplementation to multi cell-based assays can be effectively used to reduce mechanical artifacts.
14 Related JoVE Articles!
Isolation of Stem Cells from Human Pancreatic Cancer Xenografts
Institutions: Johns Hopkins University School of Medicine.
Cancer stem cells (CSCs) have been identified in a growing number of malignancies and are functionally defined by their ability to undergo self-renewal and produce differentiated progeny1
. These properties allow CSCs to recapitulate the original tumor when injected into immunocompromised mice. CSCs within an epithelial malignancy were first described in breast cancer and found to display specific cell surface antigen expression (CD44+
. Since then, CSCs have been identified in an increasing number of other human malignancies using CD44 and CD24 as well as a number of other surface antigens. Physiologic properties, including aldehyde dehydrogenase (ALDH) activity, have also been used to isolate CSCs from malignant tissues3-5
Recently, we and others identified CSCs from pancreatic adenocarcinoma based on
ALDH activity and the expression of the cell surface antigens CD44 and CD24, and CD1336-8
. These highly tumorigenic populations may or may not be overlapping and display other functions. We found that ALDH+
pancreatic CSCs are similarly tumorigenic, but ALDH+
cells are relatively more invasive8
. In this protocol we describe a method to isolate viable pancreatic CSCs from low-passage human
. Xenografted tumors are harvested from mice and made into a single-cell suspension. Tissue debris and dead cells are separated from live cells and then stained using antibodies against CD44 and CD24 and using the ALDEFLUOR reagent,
a fluorescent substrate of ALDH10
. CSCs are then isolated by fluorescence activated cell sorting. Isolated CSCs can then be used for analytical or functional assays requiring viable cells.
Cellular Biology, Issue 43, mouse models, pancreatic cancer, cancer stem cell, xenograft, fluorescent activated cell sorting, aldehyde dehydrogenase, CD44, CD24
In vitro Enrichment of Ovarian Cancer Tumor-initiating Cells
Institutions: National Cancer Institute.
Evidence suggests that small subpopulations of tumor cells maintain a unique self-renewing and differentiation capacity and may be responsible for tumor initiation and/or relapse. Clarifying the mechanisms by which these tumor-initiating cells (TICs) support tumor formation and progression could lead to the development of clinically favorable therapies. Ovarian cancer is a heterogeneous and highly recurrent disease. Recent studies suggest TICs may play an important role in disease biology. We have identified culture conditions that enrich for TICs from ovarian cancer cell lines. Growing either adherent cells or non-adherent ‘floater’ cells in a low attachment plate with serum free media in the presence of growth factors supports the propagation of ovarian cancer TICs with stem cell markers (CD133 and ALDH activity) and increased tumorigenicity without the need to physically separate the TICs from other cell types within the culture. Although the presence of floater cells is not common for all cell lines, this population of cells with innate low adherence may have high tumorigenic potential.Compared to adherent cells grown in the presence of serum, TICs readily form spheres, are significantly more tumorigenic in mice, and express putative stem cell markers. The conditions are easy to establish in a timely manner and can be used to study signaling pathways important for maintaining stem characteristics, and to identify drugs or combinations of drugs targeting TICs. The culture conditions described herein are applicable for a variety of ovarian cancer cells of epithelial origin and will be critical in providing new information about the role of TICs in tumor initiation, progression, and relapse.
Medicine, Issue 96, Ovarian cancer, tumor-initiating cells, cancer stem cell, tumorigenicity, spheroid, mouse, gynecological cancer
Studying Pancreatic Cancer Stem Cell Characteristics for Developing New Treatment Strategies
Institutions: Spanish National Cancer Research Center, Institute for Research in Biomedicine (IRB Barcelona), Queen Mary University of London.
Pancreatic ductal adenocarcinoma (PDAC) contains a subset of exclusively tumorigenic cancer stem cells (CSCs) which have been shown to drive tumor initiation, metastasis and resistance to radio- and chemotherapy. Here we describe a specific methodology for culturing primary human pancreatic CSCs as tumor spheres in anchorage-independent conditions. Cells are grown in serum-free, non-adherent conditions in order to enrich for CSCs while their more differentiated progenies do not survive and proliferate during the initial phase following seeding of single cells. This assay can be used to estimate the percentage of CSCs present in a population of tumor cells. Both size (which can range from 35 to 250 micrometers) and number of tumor spheres formed represents CSC activity harbored in either bulk populations of cultured cancer cells or freshly harvested and digested tumors 1,2
. Using this assay, we recently found that metformin selectively ablates pancreatic CSCs; a finding that was subsequently further corroborated by demonstrating diminished expression of pluripotency-associated genes/surface markers and reduced in vivo
tumorigenicity of metformin-treated cells. As the final step for preclinical development we treated mice bearing established tumors with metformin and found significantly prolonged survival. Clinical studies testing the use of metformin in patients with PDAC are currently underway (e.g.,
NCT01210911, NCT01167738, and NCT01488552). Mechanistically, we found that metformin induces a fatal energy crisis in CSCs by enhancing reactive oxygen species (ROS) production and reducing mitochondrial transmembrane potential. In contrast, non-CSCs were not eliminated by metformin treatment, but rather underwent reversible cell cycle arrest. Therefore, our study serves as a successful example for the potential of in vitro
sphere formation as a screening tool to identify compounds that potentially target CSCs, but this technique will require further in vitro
and in vivo
validation to eliminate false discoveries.
Medicine, Issue 100, Pancreatic ductal adenocarcinoma, cancer stem cells, spheres, metformin (met), metabolism
Generation of a Novel Dendritic-cell Vaccine Using Melanoma and Squamous Cancer Stem Cells
Institutions: University of Michigan, University of Michigan, University of Michigan.
We identified cancer stem cell (CSC)-enriched populations from murine melanoma D5 syngeneic to C57BL/6 mice and the squamous cancer SCC7 syngeneic to C3H mice using ALDEFLUOR/ALDH as a marker, and tested their immunogenicity using the cell lysate as a source of antigens to pulse dendritic cells (DCs). DCs pulsed with ALDHhigh
CSC lysates induced significantly higher protective antitumor immunity than DCs pulsed with the lysates of unsorted whole tumor cell lysates in both models and in a lung metastasis setting and a s.c.
tumor growth setting, respectively. This phenomenon was due to CSC vaccine-induced humoral as well as cellular anti-CSC responses. In particular, splenocytes isolated from the host subjected to CSC-DC vaccine produced significantly higher amount of IFNγ and GM-CSF than splenocytes isolated from the host subjected to unsorted tumor cell lysate pulsed-DC vaccine. These results support the efforts to develop an autologous CSC-based therapeutic vaccine for clinical use in an adjuvant setting.
Cancer Biology, Issue 83, Cancer stem cell (CSC), Dendritic cells (DC), Vaccine, Cancer immunotherapy, antitumor immunity, aldehyde dehydrogenase
Mosaic Zebrafish Transgenesis for Functional Genomic Analysis of Candidate Cooperative Genes in Tumor Pathogenesis
Institutions: Mayo Clinic College of Medicine, Center for Individualized Medicine, Tufts University School of Medicine, Mayo Clinic.
Comprehensive genomic analysis has uncovered surprisingly large numbers of genetic alterations in various types of cancers. To robustly and efficiently identify oncogenic “drivers” among these tumors and define their complex relationships with concurrent genetic alterations during tumor pathogenesis remains a daunting task. Recently, zebrafish have emerged as an important animal model for studying human diseases, largely because of their ease of maintenance, high fecundity, obvious advantages for in vivo
imaging, high conservation of oncogenes and their molecular pathways, susceptibility to tumorigenesis and, most importantly, the availability of transgenic techniques suitable for use in the fish. Transgenic zebrafish models of cancer have been widely used to dissect oncogenic pathways in diverse tumor types. However, developing a stable transgenic fish model is both tedious and time-consuming, and it is even more difficult and more time-consuming to dissect the cooperation of multiple genes in disease pathogenesis using this approach, which requires the generation of multiple transgenic lines with overexpression of the individual genes of interest followed by complicated breeding of these stable transgenic lines. Hence, use of a mosaic transient transgenic approach in zebrafish offers unique advantages for functional genomic analysis in vivo
. Briefly, candidate transgenes can be coinjected into one-cell-stage wild-type or transgenic zebrafish embryos and allowed to integrate together into each somatic cell in a mosaic pattern that leads to mixed genotypes in the same primarily injected animal. This permits one to investigate in a faster and less expensive manner whether and how the candidate genes can collaborate with each other to drive tumorigenesis. By transient overexpression of activated ALK
in the transgenic fish overexpressing MYCN
, we demonstrate here the cooperation of these two oncogenes in the pathogenesis of a pediatric cancer, neuroblastoma that has resisted most forms of contemporary treatment.
Developmental Biology, Issue 97, zebrafish, animal model, mosaic transgenesis, coinjection, functional genomics, tumor initiation
A Toolkit to Enable Hydrocarbon Conversion in Aqueous Environments
Institutions: Delft University of Technology, Delft University of Technology.
This work puts forward a toolkit that enables the conversion of alkanes by Escherichia coli
and presents a proof of principle of its applicability. The toolkit consists of multiple standard interchangeable parts (BioBricks)9
addressing the conversion of alkanes, regulation of gene expression and survival in toxic hydrocarbon-rich environments.
A three-step pathway for alkane degradation was implemented in E. coli
to enable the conversion of medium- and long-chain alkanes to their respective alkanols, alkanals and ultimately alkanoic-acids. The latter were metabolized via the native β-oxidation pathway. To facilitate the oxidation of medium-chain alkanes (C5-C13) and cycloalkanes (C5-C8), four genes (alkB2
) of the alkane hydroxylase system from Gordonia
were transformed into E. coli
. For the conversion of long-chain alkanes (C15-C36), theladA
gene from Geobacillus thermodenitrificans
was implemented. For the required further steps of the degradation process, ADH
and ALDH (
originating from G. thermodenitrificans
) were introduced10,11
. The activity was measured by resting cell assays. For each oxidative step, enzyme activity was observed.
To optimize the process efficiency, the expression was only induced under low glucose conditions: a substrate-regulated promoter, pCaiF, was used. pCaiF is present in E. coli
K12 and regulates the expression of the genes involved in the degradation of non-glucose carbon sources.
The last part of the toolkit - targeting survival - was implemented using solvent tolerance genes, PhPFDα and β, both from Pyrococcus horikoshii
OT3. Organic solvents can induce cell stress and decreased survivability by negatively affecting protein folding. As chaperones, PhPFDα and β improve the protein folding process e.g.
under the presence of alkanes. The expression of these genes led to an improved hydrocarbon tolerance shown by an increased growth rate (up to 50%) in the presences of 10% n
-hexane in the culture medium were observed.
Summarizing, the results indicate that the toolkit enables E. coli
to convert and tolerate hydrocarbons in aqueous environments. As such, it represents an initial step towards a sustainable solution for oil-remediation using a synthetic biology approach.
Bioengineering, Issue 68, Microbiology, Biochemistry, Chemistry, Chemical Engineering, Oil remediation, alkane metabolism, alkane hydroxylase system, resting cell assay, prefoldin, Escherichia coli, synthetic biology, homologous interaction mapping, mathematical model, BioBrick, iGEM
Isolation, Enrichment, and Maintenance of Medulloblastoma Stem Cells
Institutions: Vanderbilt University.
Brain tumors have been suggested to possess a small population of stem cells that are the root cause of tumorigenesis. Neurosphere assays have been generally adopted to study the nature of neural stem cells, including those derived from normal and tumorous tissues. However, appreciable amounts of differentiation and cell death are common in cultured neurospheres likely due to sub-optimal condition such as accessibility of all cells within sphere aggregates to culture medium.
Medulloblastoma, the most common pediatric CNS tumor, is characterized by its rapid progression and tendency to spread along the entire brain-spinal axis with dismal clinical outcome. Medulloblastoma is a neuroepithelial tumor of the cerebellum, accounting for 20% and 40% of intracranial and posterior fossa tumor in childhood, respectively1
. It is now well established that Shh signaling stimulates proliferation of cerebellar granule neuron precursors (CGNPs) during cerebellar development 2-4
. Numerous studies using mouse models, in which the Shh pathway is constitutively activated, have linked Shh signaling with medulloblastoma 5-9
A recent report has shown that a subset of medulloblastoma cells derived from Patched1LacZ/+
mice are cancer stem cells, which are capable of initiating and propogating tumors 10
. Here we describe an efficient method to isolate, enrich and maintain tumor stem cells derived from several mouse models of medulloblastoma, with constitutively activated Shh pathway due to a mutation in Smoothened (11
, hereon referred as SmoM2), a GPCR that is critical for Shh pathway activation. In every isolated medulloblastoma tissue, we were able to establish numerous highly proliferative colonies. These cells robustly expressed several neural stem cell markers such as Nestin and Sox2, can undergo serial passages (greater than 20) and were clonogenic. While these cultured tumor stem cells were relatively small, often bipoar with high nuclear to cytoplasmic ratio when cultured under conditions favoring stem cell growth, they dramatically altered their morphology, extended multiple cellular processes, flattened and withdrew from the cell cycle upon switching to a cell culture medium supplemented with 10% fetal bovine serum. More importantly, these tumor stem cells differentiated into Tuj1+ or NeuN+ neurons, GFAP+ astrocytes and CNPase+ oligodendrocytes, thus highlighting their multi-potency. Furthermore, these cells were capable of propagating secondary medulloblastomas when orthotopically transplanted into host mice.
Medicine, Issue 43, medulloblastoma, stem cells, isolation, in vitro culture
Optimization of High Grade Glioma Cell Culture from Surgical Specimens for Use in Clinically Relevant Animal Models and 3D Immunochemistry
Institutions: Henry Ford Hospital.
Glioblastomas, the most common and aggressive form of astrocytoma, are refractory to therapy, and molecularly heterogeneous. The ability to establish cell cultures that preserve the genomic profile of the parental tumors, for use in patient specific in vitro
and in vivo
models, has the potential to revolutionize the preclinical development of new treatments for glioblastoma tailored to the molecular characteristics of each tumor.
Starting with fresh high grade astrocytoma tumors dissociated into single cells, we use the neurosphere assay as an enrichment method for cells presenting cancer stem cell phenotype, including expression of neural stem cell markers, long term self-renewal in vitro
, and the ability to form orthotopic xenograft tumors. This method has been previously proposed, and is now in use by several investigators. Based on our experience of dissociating and culturing 125 glioblastoma specimens, we arrived at the detailed protocol we present here, suitable for routine neurosphere culturing of high grade astrocytomas and large scale expansion of tumorigenic cells for preclinical studies. We report on the efficiency of successful long term cultures using this protocol and suggest affordable alternatives for culturing dissociated glioblastoma cells that fail to grow as neurospheres. We also describe in detail a protocol for preserving the neurospheres 3D architecture for immunohistochemistry. Cell cultures enriched in CSCs, capable of generating orthotopic xenograft models that preserve the molecular signatures and heterogeneity of GBMs, are becoming increasingly popular for the study of the biology of GBMs and for the improved design of preclinical testing of potential therapies.
Medicine, Issue 83, Primary Cell Culture, animal models, Nervous System Diseases, Neoplasms, glioblastoma, neurosphere, surgical specimens, long-term self-renewal
Mammosphere Formation Assay from Human Breast Cancer Tissues and Cell Lines
Institutions: Imperial College London.
Similar to healthy tissues, many blood and solid malignancies are now thought to be organised hierarchically, with a subset of stem-like cancer cells that self-renew while giving rise to more differentiated progeny. Understanding and targeting these cancer stem cells in breast cancer, which may possess enhanced chemo- and radio-resistance compared to the non-stem tumor bulk, has become an important research area. Markers including CD44, CD24, and ALDH activity can be assessed using fluorescence activated cell sorting (FACS) to prospectively isolate cells that display enhanced tumorigenicity when implanted into immunocompromised mice: the mammosphere assay has also become widely used for its ability to retrospectively identify sphere-forming cells that develop from single stem cell-like clones. Here we outline approaches for the appropriate culturing of mammospheres from cell lines or primary patient samples, their passaging, and calculations to estimate sphere forming efficiency (SFE). First we discuss key considerations and pitfalls in the appropriate planning and interpretation of mammosphere experiments.
Medicine, Issue 97, breast cancer, cancer stem cell, CSC, BCSC, tumorsphere, mammosphere, tumorigenesis, self-renewal.
Normal and Malignant Muscle Cell Transplantation into Immune Compromised Adult Zebrafish
Institutions: Massachusetts General Hospital, Harvard Stem Cell Institute, Universidade do Porto.
Zebrafish have become a powerful tool for assessing development, regeneration, and cancer. More recently, allograft cell transplantation protocols have been developed that permit engraftment of normal and malignant cells into irradiated, syngeneic, and immune compromised adult zebrafish. These models when coupled with optimized cell transplantation protocols allow for the rapid assessment of stem cell function, regeneration following injury, and cancer. Here, we present a method for cell transplantation of zebrafish adult skeletal muscle and embryonal rhabdomyosarcoma (ERMS), a pediatric sarcoma that shares features with embryonic muscle, into immune compromised adult rag2E450fs
homozygous mutant zebrafish. Importantly, these animals lack T cells and have reduced B cell function, facilitating engraftment of a wide range of tissues from unrelated donor animals. Our optimized protocols show that fluorescently labeled muscle cell preparations from α-actin-RFP
transgenic zebrafish engraft robustly when implanted into the dorsal musculature of rag2
homozygous mutant fish. We also demonstrate engraftment of fluorescent-transgenic ERMS where fluorescence is confined to cells based on differentiation status. Specifically, ERMS were created in AB-strain myf5-GFP; mylpfa-mCherry
double transgenic animals and tumors injected into the peritoneum of adult immune compromised fish. The utility of these protocols extends to engraftment of a wide range of normal and malignant donor cells that can be implanted into dorsal musculature or peritoneum of adult zebrafish.
Immunology, Issue 94, zebrafish, immune compromised, transplantation, muscle, rhabdomyosarcoma, rag2E450fs, rag2fb101, fluorescent, transgenic
Patient Derived Cell Culture and Isolation of CD133+ Putative Cancer Stem Cells from Melanoma
Institutions: Charité - Universitätsmedizin Berlin, Free University Berlin, Charité - Universitätsmedizin Berlin, Charité - Universitätsmedizin Berlin.
Despite improved treatments options for melanoma available today, patients with advanced malignant melanoma still have a poor prognosis for progression-free and overall survival. Therefore, translational research needs to provide further molecular evidence to improve targeted therapies for malignant melanomas. In the past, oncogenic mechanisms related to melanoma were extensively studied in established cell lines. On the way to more personalized treatment regimens based on individual genetic profiles, we propose to use patient-derived cell lines instead of generic cell lines. Together with high quality clinical data, especially on patient follow-up, these cells will be instrumental to better understand the molecular mechanisms behind melanoma progression.
Here, we report the establishment of primary melanoma cultures from dissected fresh tumor tissue. This procedure includes mincing and dissociation of the tissue into single cells, removal of contaminations with erythrocytes and fibroblasts as well as primary culture and reliable verification of the cells' melanoma origin.
Recent reports revealed that melanomas, like the majority of tumors, harbor a small subpopulation of cancer stem cells (CSCs), which seem to exclusively fuel tumor initiation and progression towards the metastatic state. One of the key markers for CSC identification and isolation in melanoma is CD133. To isolate CD133+
CSCs from primary melanoma cultures, we have modified and optimized the Magnetic-Activated Cell Sorting (MACS) procedure from Miltenyi resulting in high sorting purity and viability of CD133+
CSCs and CD133-
bulk, which can be cultivated and functionally analyzed thereafter.
Cancer Biology, Issue 73, Medicine, Stem Cell Biology, Cellular Biology, Molecular Biology, Biomedical Engineering, Genetics, Oncology, Primary cell culture, melanoma, MACS, cancer stem cells, CD133, cancer, prostate cancer cells, melanoma, stem cells, cell culture, personalized treatment
Isolation of Cancer Stem Cells From Human Prostate Cancer Samples
Institutions: Icahn School of Medicine at Mount Sinai, Memorial Sloan-Kettering Cancer Center.
The cancer stem cell (CSC) model has been considerably revisited over the last two decades. During this time CSCs have been identified and directly isolated from human tissues and serially propagated in immunodeficient mice, typically through antibody labeling of subpopulations of cells and fractionation by flow cytometry. However, the unique clinical features of prostate cancer have considerably limited the study of prostate CSCs from fresh human tumor samples. We recently reported the isolation of prostate CSCs directly from human tissues by virtue of their HLA class I (HLAI)-negative phenotype. Prostate cancer cells are harvested from surgical specimens and mechanically dissociated. A cell suspension is generated and labeled with fluorescently conjugated HLAI and stromal antibodies. Subpopulations of HLAI-negative cells are finally isolated using a flow cytometer. The principal limitation of this protocol is the frequently microscopic and multifocal nature of primary cancer in prostatectomy specimens. Nonetheless, isolated live prostate CSCs are suitable for molecular characterization and functional validation by transplantation in immunodeficient mice.
Medicine, Issue 85, Cancer Stem Cells, Tumor Initiating Cells, Prostate Cancer, HLA class I, Primary Prostate Cancer, Castration Resistant Prostate Cancer, Metastatic Prostate Cancer, Human Tissue Samples, Intratumoral heterogeneity
Enrichment for Chemoresistant Ovarian Cancer Stem Cells from Human Cell Lines
Institutions: Indiana University School of Medicine.
Cancer stem cells (CSCs) are defined as a subset of slow cycling and undifferentiated cells that divide asymmetrically to generate highly proliferative, invasive, and chemoresistant tumor cells. Therefore, CSCs are an attractive population of cells to target therapeutically. CSCs are predicted to contribute to a number of types of malignancies including those in the blood, brain, lung, gastrointestinal tract, prostate, and ovary. Isolating and enriching a tumor cell population for CSCs will enable researchers to study the properties, genetics, and therapeutic response of CSCs. We generated a protocol that reproducibly enriches for ovarian cancer CSCs from ovarian cancer cell lines (SKOV3 and OVCA429). Cell lines are treated with 20 µM cisplatin for 3 days. Surviving cells are isolated and cultured in a serum-free stem cell media containing cytokines and growth factors. We demonstrate an enrichment of these purified CSCs by analyzing the isolated cells for known stem cell markers Oct4, Nanog, and Prom1 (CD133) and cell surface expression of CD177 and CD133. The CSCs exhibit increased chemoresistance. This method for isolation of CSCs is a useful tool for studying the role of CSCs in chemoresistance and tumor relapse.
Medicine, Issue 91, cancer stem cells, stem cell markers, ovarian cancer, chemoresistance, cisplatin, cancer progression
Flat Mount Preparation for Observation and Analysis of Zebrafish Embryo Specimens Stained by Whole Mount In situ Hybridization
Institutions: University of Notre Dame.
The zebrafish embryo is now commonly used for basic and biomedical research to investigate the genetic control of developmental processes and to model congenital abnormalities. During the first day of life, the zebrafish embryo progresses through many developmental stages including fertilization, cleavage, gastrulation, segmentation, and the organogenesis of structures such as the kidney, heart, and central nervous system. The anatomy of a young zebrafish embryo presents several challenges for the visualization and analysis of the tissues involved in many of these events because the embryo develops in association with a round yolk mass. Thus, for accurate analysis and imaging of experimental phenotypes in fixed embryonic specimens between the tailbud and 20 somite stage (10 and 19 hours post fertilization (hpf), respectively), such as those stained using whole mount in situ
hybridization (WISH), it is often desirable to remove the embryo from the yolk ball and to position it flat on a glass slide. However, performing a flat mount procedure can be tedious. Therefore, successful and efficient flat mount preparation is greatly facilitated through the visual demonstration of the dissection technique, and also helped by using reagents that assist in optimal tissue handling. Here, we provide our WISH protocol for one or two-color detection of gene expression in the zebrafish embryo, and demonstrate how the flat mounting procedure can be performed on this example of a stained fixed specimen. This flat mounting protocol is broadly applicable to the study of many embryonic structures that emerge during early zebrafish development, and can be implemented in conjunction with other staining methods performed on fixed embryo samples.
Developmental Biology, Issue 89, animals, vertebrates, fishes, zebrafish, growth and development, morphogenesis, embryonic and fetal development, organogenesis, natural science disciplines, embryo, whole mount in situ hybridization, flat mount, deyolking, imaging