Unknown,Transcriptomics,Genomics,Proteomics

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Expression data from early zebrafish embryos

ABSTRACT: In the early zebrafish embryo, the developing genome profile can be interfered with by exposure to pentachlorophenol, and some specific sets of genes are up-regulated or down-regulated. We used microarrays to detail the global program of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. Zebrafish embryos were selected at successive stages of early development for RNA extraction and hybridization on Affymetrix microarrays. We selected embryos exposed to 20 ug/L pentachlorophenol (C1), 50 ug/L pentachlorophenol (C2), and deionized water control (C3) at the gastrula stage (about 8hpf).

ORGANISM(S): Danio rerio

SUBMITTER: Ting Xu

PROVIDER: E-GEOD-37019 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Gene expression was measured using microarrays in 8 hour postfertilization embryos, comparing control versus ethanol-treated (2 to 8 hours postfertilization) embryos. This experiment was performed to determine the gene expression changes that occur in response to ethanol treatment as a model of fetal alcohol spectrum disorder. Fetal alcohol spectrum disorder (FASD) occurs when pregnant mothers consume alcohol, causing embryonic ethanol exposure and characteristic birth defects that include craniofacial, neural and cardiac defects. Gastrulation is a particularly sensitive developmental stage for teratogen exposure, and zebrafish is an outstanding model to study gastrulation and FASD. Epiboly (spreading blastomere cells over the yolk cell), prechordal plate migration and convergence/extension cell movements are sensitive to early ethanol exposure. Here, experiments are presented to characterize mechanisms of ethanol toxicity on epiboly and gastrulation. Epiboly mechanisms include blastomere radial intercalation cell movements and yolk cell microtubule cytoskeleton pulling the embryo to the vegetal pole. Both of these processes were disrupted by ethanol exposure. Ethanol effects on cell migration also indicated that cell adhesion was affected, which was confirmed by cell aggregation assays. E-cadherin cell adhesion molecule expression and distribution, which control epiboly and gastrulation, were not affected. Gene expression microarray analysis was used to identify potential causative factors for early development defects, and expression of the cell adhesion molecule protocadherin-18a (pcdh18a), which controls epiboly, was significantly reduced in ethanol-exposed embryos. Injecting pcdh18a synthetic mRNA in ethanol-treated embryos partially rescued epiboly cell movements, including enveloping layer cell shape changes. Together, data show that epiboly and gastrulation defects induced by ethanol are multifactorial, and include yolk cell (extraembryonic tissue) microtubule cytoskeleton disruption and blastomere adhesion defects, in part caused by reduced pcdh18a expression. Control vs. ethanol-treated zebrafish embryos that were treated from 2 to 8 hours postfertilization. Total RNA from control and ethanol-treated embryos were harvested at 8 hours postfertilization.

Project description:Gene expression profiling has provided critical insights into the molecular pathways underlying development of model organisms, however little information is available on regulated gene expression during human embryogenesis. We have now filled this important gap of knowledge by performing genome-wide microarray analysis of the Homo sapiens gene expression during the 4-9th week, a period when most organs develop. We analyzed individually 3 embryos for each of the 4th, 5th, 6th, 7th, 8th, and 9th week of human embryonic development by using the Affymetrix U133 plus 2.0 human GeneChip array.About half of all human genes are expressed and 18.6% of the expressed genes were significantly regulated during this important period. We further identified over 5000 regulated genes, most of which were previously not known to be associated with animal development. Our study also revealed that the genes involved here are distinct from those during early embryogenesis, which include three groups of maternal genes. Furthermore, we discovered that genes in a given developmental process are coordinately regulated. This led us to develop an easily searchable database of this entire collection of gene expression profiles, allowing for identification new genes important for a particular developmental process/pathway and deducing the potential function of a novel gene. The validity of the predictions from the database was demonstrated with two examples through spatiotemporal analyses of the two novel genes. Such a database should serve as a highly valuable resource for the molecular analysis of human development and pathogenesis. Human embryos were obtained from therapeutic termination of pregnancy induced by Mifepristone. Morphologically normal embryos were selected and staged according to the Carnegie classification and the Chinese embryonic developmental characteristics. Each whole embryo was micro-dissected from an intact trophoblast and stored directly in liquid nitrogen or homogenized using Trizol solution and then stored at -80oC. Total RNA was isolated from each whole embryo individually and each of the 3 RNA samples for each developmental time point was independently analyzed on a Human U133 plus 2.0 Genome Oligonucleotide Array.

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Expression data from early zebrafish embryos

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