Factorial Microarray Analysis of Zebrafish Retinal Development
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ABSTRACT:
ORGANISM(S): Danio rerio
PROVIDER: GSE8874 | GEO | 2008/08/04
SECONDARY ACCESSION(S): PRJNA102245
REPOSITORIES: GEO
Similar Datasets
Project description:Retinal cells are specified in a zebrafish recessive mutant called young (yng) but they fail to terminally differentiate; i.e. extend neurites and make synaptic contacts. A point mutation in a brahma-related gene 1 (brg1) is responsible for this phenotype. In this microarray study, a three-factor factorial design was utilized to investigate the effects of 1) mutation, 2) change in time (36 vs. 52hpf), and 3) change in tissue (retina vs. whole embryos), and their interactions on gene expression. Significant probesets were inferred by using both specific contrasts of the fitted Analysis of Variance (ANOVA) models and a corresponding 2-fold expression cutoff. The probesets were grouped into three broad categories: 1) Brg1-regulated retinal differentiation genes (731 probsets), 2) Retinal specific genes but independent of Brg1 regulation (3038 probesets) and 3) Genes regulated by Brg1 but outside the retina (107 probesets). Four gene groups/pathways including neurite outgrowth regulators, Delta-Notch signalling molecules, Irx family members and specific cell cycle regulators were identified in the first group, and their relevance for retinal differentiation functionally validated. This study demonstrates that an approach such as ours can identify relevant genes and pathways involved in retinal development as well as the development of other tissues at the same time. Experiment Overall Design: The gene expression levels of three independent replicates of retina consisting of ten samples each at 36 and 52hpf retinas from WT (WR36 & WR52) and yng (YR36 & YR52) larvae, and stage-matched whole embryos: WT at 36hpf (WA36), WT at 52hpf (WA52), yng at 36hpf (YA36), and yng at 52hpf (YA52) were measured by Affymetrix Zebrafish Whole Genome Arrays. We analyzed the effects of these factors on gene expression levels: 1) mutation (M), 2) tissue (R), and 3) time (T). Each of these factors have two levels: mutant and WT (M); retinas and whole body (R); and 36 and 52 hpf (T). As a result, there are totally eight conditions for all the comparisons and the design is called a 2x2x2 factorial design. The aim of a factorial analysis is to delineate the effects of each factor and their combinations (interaction) on gene expression. The overall analysis strategy is to first fit a full Analysis of Variance (ANOVA) model with all possible main effects (T, M, R) and their interactions (T*M, M*R, R*M, T*M*R) to the gene expression data for each probeset. The estimates of the model are obtained through a maximum likelihood estimation method. Then a backward elimination strategy is used to remove insignificant main effects and interactions to get the most parsimonious models. Finally, a group of contrasts and their corresponding fold changes are used to infer whether that probeset is significantly associated with a particular biological process.
2008-10-18 | E-GEOD-8874 | biostudies-arrayexpress
Project description:Retinal development requires precise temporal and spatial coordination of cell cycle exit, cell-fate specification, cell migration and differentiation. When this process is disrupted, retinoblastoma, a developmental tumor of the retina, can form. Epigenetic modulators are central to precisely coordinating developmental events, and many epigenetic processes have been implicated in cancer. Studying epigenetic mechanisms in development is challenging because they often regulate multiple cellular processes; therefore, elucidating the primary molecular mechanisms involved can be difficult. Here we explore the role of Brg1 in retinal development and retinoblastoma by using molecular and cellular approaches. Brg1 regulated retinal size by controlling cell cycle length, cell cycle exit, and cell survival during development. Brg1 was not required for cell-fate specification but was required for photoreceptor differentiation and cell adhesion/polarity programs that contribute to proper retinal lamination during development. The combination of defective cell differentiation and lamination led to retinal degeneration in Brg1-deficient retinae. Despite the hypocellularity, premature cell cycle exit, increased cell death, and extended cell cycle length, retinal progenitor cells persisted in Brg1-deficient retinae, thereby making them more susceptible to retinoblastoma. ChIP-seq analysis provided insight into the underlying molecular mechanisms of these complex Brg1-regulated cellular processes during retinal development.
2015-12-02 | GSE74268 | GEO
Project description:Retinal development requires precise temporal and spatial coordination of cell cycle exit, cell-fate specification, cell migration and differentiation. When this process is disrupted, retinoblastoma, a developmental tumor of the retina, can form. Epigenetic modulators are central to precisely coordinating developmental events, and many epigenetic processes have been implicated in cancer. Studying epigenetic mechanisms in development is challenging because they often regulate multiple cellular processes; therefore, elucidating the primary molecular mechanisms involved can be difficult. Here we explore the role of Brg1 in retinal development and retinoblastoma by using molecular and cellular approaches. Brg1 regulated retinal size by controlling cell cycle length, cell cycle exit, and cell survival during development. Brg1 was not required for cell-fate specification but was required for photoreceptor differentiation and cell adhesion/polarity programs that contribute to proper retinal lamination during development. The combination of defective cell differentiation and lamination led to retinal degeneration in Brg1-deficient retinae. Despite the hypocellularity, premature cell cycle exit, increased cell death, and extended cell cycle length, retinal progenitor cells persisted in Brg1-deficient retinae, thereby making them more susceptible to retinoblastoma. ChIP-seq analysis provided insight into the underlying molecular mechanisms of these complex Brg1-regulated cellular processes during retinal development.
2015-12-02 | GSE74181 | GEO
Project description:Eye development and photoreceptor maintenance requires the retinal pigment epithelium (RPE), a thin layer of cells that underlies the neural retina. Despite its importance, RPE development has not been studied by a genomic approach. A microarray expression profiling methodology was established in this study for studying RPE development. The intact retina with RPE attached was dissected from developing embryos, and differentially expressed genes in RPE were inferred by comparing the dissected tissues with retinas without RPE using microarray and statistical analyses. We found 8810 probesets to be significantly expressed in RPE at 52 hours post-fertilization (hpf), of which 1443 might have biologically meaningful expression levels. Further, 78 and 988 probesets were found to be significantly over- or under-expressed in RPE respectively compared to retina. Also, 79.2% (38/48) of the known over-expressed probesets have been independently validated as RPE-related transcripts. The results strongly suggest that this methodology can obtain in vivo RPE specific gene expression from the zebrafish embryos and identify novel RPE markers. Keywords: Development, retina, retinal pigment epithelium
2007-01-25 | GSE5048 | GEO
Project description:Eye development and photoreceptor maintenance requires the retinal pigment epithelium (RPE), a thin layer of cells that underlies the neural retina. Despite its importance, RPE development has not been studied by a genomic approach. A microarray expression profiling methodology was established in this study for studying RPE development. The intact retina with RPE attached was dissected from developing embryos, and differentially expressed genes in RPE were inferred by comparing the dissected tissues with retinas without RPE using microarray and statistical analyses. We found 8810 probesets to be significantly expressed in RPE at 52 hours post-fertilization (hpf), of which 1443 might have biologically meaningful expression levels. Further, 78 and 988 probesets were found to be significantly over- or under-expressed in RPE respectively compared to retina. Also, 79.2% (38/48) of the known over-expressed probesets have been independently validated as RPE-related transcripts. The results strongly suggest that this methodology can obtain in vivo RPE specific gene expression from the zebrafish embryos and identify novel RPE markers. Experiment Overall Design: The gene expression levels of three independent replicates of retina with RPE attached consisting of ten samples each at 52hpf (WRR52) were compared with three independent pure retinal samples consisting of ten retinas each at 52hpf (WR52). The yield-adjusted WR52 expression values were assumed to be equivalent to the retinal contribution in WRR52 samples and deducted from WRR52 expression values to obtain estimations of RPE gene expression at 52hpf (RPE52). Differential gene expressions between RPE and retina were inferred by comparing the RPE52 estimates and WR52 expression values.
2008-06-13 | E-GEOD-5048 | biostudies-arrayexpress
Project description:Purpose: The purpose of this study was to develop a framework for analyzing RPE expression profiles from zebrafish eye mutants. Methods: The fish model we used was smarca4 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 4), a retinal dystrophic mutant that the retinal phenotype and expression profiles were previously characterized. Histological and Affymetrix GeneChip analyses were conducted to define the RPE defects and underlying differential expression respectively. Results: Histological analysis indicates that smarca4 RPE was formed but its differentiation was abnormal. In particular, ultra-structural analysis of smarca4 RPE by transmission electron microscopy showed a number of defects in melanogenesis, suggesting that the cytoskeletal dynamics was impaired. To compare the expression profile of normal wild-type (WT) and smarca4 RPE, their retinas and RPE-attached retinas were microdissected and the gene expression values of these tissues measured by Affymetrix GeneChip analysis. The RPE expression values were then estimated from these samples using an approach previously established by us. A factorial analysis was conducted using the expression values of RPE, retinal as well as the whole-embryo samples. Specific rules (contrasts) were built using the coefficients of the resulting fitted model to select for three groups of genes: 1) Smarca4-regulated RPE genes, 2) Smarca4-regulated retinal genes, and 3) Smarca4-regulated RPE genes that are not differentially expressed in the retina. The latter group consists of 39 genes that are highly related to cytoskeletal dynamics, melanogenesis, paracrine and intracellular signal transduction. Conclusions: Our analytical framework can potentially identify genes in zebrafish mutants that both retina and RPE are affected by the underlying mutation. The gene expression levels of three independent replicates of WT whole embryos (WA52), WT retinas (WR52), WT RPE-attached retinas (WRR52), smarca4/yng retinas (YR52), smarca4 RPE-attached retinas (YRR52) and smarca4 whole embryos (YA52) were measured by Affymetrix Zebrafish Whole Genome Arrays. All samples were collected at 52 hpf. The probe-level data of these sample groups were background adjusted, normalized and summarized by a robust multiarray average (RMA) algorithm. RPE expression values were estimated from the comparison between the retinal and RPE-attached retinal samples of the same genotype based on a method we previously developed (Leung et al., Invest Ophthalmol Vis Sci. 2007; 48:881). Then, a 3x2 factorial design was used to analyze the expression values of three kinds of tissue (T): whole embryo, retina and RPE in two kinds of mutation (M) background: WT and smarca4. Using the coefficients from the fitted models, contrasts were built to identify candidate genes that fulfilled specific criteria. The false discovery rate (FDR) q-value cutoff for a contrast was 0.001. Several contrasts were ultimately combined to allow for selection of genes that were regulated by Smarca4 in the retina and RPE. These include 1) Smarca4-regulated RPE genes, 2) Smarca4-regulated retinal genes, and 3) Smarca4-regulated RPE genes that are not differentially expressed in the retina.
2014-01-03 | E-GEOD-50241 | biostudies-arrayexpress
Project description:We applied a custom 2k micro-array with 2232 oligonucleotide sequences (50-70 nt) to a factorial with 29 parental inbred lines (16 Dent,13 Flint) of European maize (Zea mays L.). The selection of oligonucleotides was based on 47k-array expression data from a 14x7 factorial with 98 hybrids (GSE17754). The main fraction of oligonucleotides (1639) represents genes that showed differential expression between the parental genotypes in the 14x7 factorial and consistent association with HP for GY in cross validation runs to estimate prediction accuracies for this trait. In addition the array contains partial overlapping fractions of genes that correlated with HP/GY (378), HP/GDMC (200), or MPH/GY (345) and 205 representatives of the 6 most overrepresented biological processes among genes correlated with HP/GY in the 14x7 factorial.
2016-08-18 | GSE85285 | GEO
Project description:We applied a custom 2k micro-array with 2232 oligonucleotide sequences (50-70 nt) to a factorial with 13 parental inbred lines (9 Dent, 4 Flint) of European maize (Zea mays L.). The selection of oligonucleotides was based on 47k-array expression data from a 14x7 factorial with 98 hybrids (GSE17754). The main fraction of oligonucleotides (1639) represents genes that showed differential expression between the parental genotypes in the 14x7 factorial and consistent association with HP for GY in cross validation runs to estimate prediction accuracies for this trait. In addition the array contains partial overlapping fractions of genes that correlated with HP/GY (378), HP/GDMC (200), or MPH/GY (345) and 205 representatives of the 6 most overrepresented biological processes among genes correlated with HP/GY in the 14x7 factorial.
2016-08-18 | GSE85288 | GEO
Project description:We applied a custom 2k micro-array with 2232 oligonucleotide sequences (50-70 nt) to a factorial with 20 parental inbred lines (14 Dent, 6 Flint) of European maize (Zea mays L.). The selection of oligonucleotides was based on 47k-array expression data from a 14x7 factorial with 98 hybrids (GSE17754). The main fraction of oligonucleotides (1639) represents genes that showed differential expression between the parental genotypes in the 14x7 factorial and consistent association with HP for GY in cross validation runs to estimate prediction accuracies for this trait. In addition the array contains partial overlapping fractions of genes that correlated with HP/GY (378), HP/GDMC (200), or MPH/GY (345) and 205 representatives of the 6 most overrepresented biological processes among genes correlated with HP/GY in the 14x7 factorial.
2016-08-18 | GSE85287 | GEO
Project description:We applied a custom 2k micro-array with 2232 oligonucleotide sequences (50-70 nt) to a factorial with 13 parental inbred lines (9 Dent, 4 Flint) of European maize (Zea mays L.). The selection of oligonucleotides was based on 47k-array expression data from a 14x7 factorial with 98 hybrids (GSE17754). The main fraction of oligonucleotides (1639) represents genes that showed differential expression between the parental genotypes in the 14x7 factorial and consistent association with HP for GY in cross validation runs to estimate prediction accuracies for this trait. In addition the array contains partial overlapping fractions of genes that correlated with HP/GY (378), HP/GDMC (200), or MPH/GY (345) and 205 representatives of the 6 most overrepresented biological processes among genes correlated with HP/GY in the 14x7 factorial.
2016-08-18 | GSE85286 | GEO