Wnt signaling in early eye development, specifically the lens placode shows expression of 12 out of 19 Wnt ligands. We these Wnt activities were suppressed using conditional deletion of Wntless, dramatic phenotypic changes in morphogensis occurred.
Wnt ligands from the embryonic surface ectoderm regulate 'bimetallic strip' optic cup morphogenesis in mouse.
Specimen part
View SamplesThe coupling between cell-cycle exit and onset of differentiation is a common feature throughout the developing nervous system, but the mechanisms that link these processes are mostly unknown. Although the transcription factor Pax6 was implicated in both proliferation and differentiation of multiple regions within the CNS, its contribution to the transition between these successive states remains elusive. To gain insight into the role of Pax6 during the transition from proliferating progenitors to differentiating precursors, we investigated cell-cycle and transcriptomic changes occurring in Pax6- retinal progenitor cells (RPCs). Our analyses revealed a unique cell-cycle phenotype of the Pax6-deficient RPCs, which included a reduced number of cells in the S phase, an increased number of cells exiting the cell cycle, and delayed differentiation kinetics of Pax6- precursors. These alterations were accompanied by co-expression of factors that promote (Ccnd1, Ccnd2, Ccnd3) and inhibit (P27kip1 and P27kip2) the cell cycle. Further characterization of the changes in transcription profile of the Pax6-deficient RPCs revealed abrogated expression of multiple factors which are known to be involved in regulating proliferation of RPCs, including the transcription factors Vsx2, Nr2e1, Plagl1 and Hedgehog signaling. These findings provide novel insight into the molecular mechanism mediating the pleiotropic activity of Pax6 in RPCs. The results further suggest that rather than conveying a linear effect on RPCs, such as promoting their proliferation and inhibiting their differentiation, Pax6 regulates multiple transcriptional networks which function simultaneously, thereby conferring the capacity to proliferate, assume multiple cell fates and execute the differentiation program into retinal lineages.
Pax6 is required for normal cell-cycle exit and the differentiation kinetics of retinal progenitor cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MicroRNAs are essential for differentiation of the retinal pigmented epithelium and maturation of adjacent photoreceptors.
Specimen part, Treatment
View SamplesDysfunction of the retinal pigmented epithelium (RPE) results in degeneration of photoreceptors and vision loss and is correlated with common blinding disorders in humans. Although many protein-coding genes are known to be expressed in RPEs and important for their development and maintenance, virtually nothing is known about the in vivo roles of non-protein coding transcripts in RPEs. The expression patterns of microRNAs (miRNAs) have been analyzed in a variety of ocular tissues, and few were implicated to play role in RPE based on studies in cell lines. Herein, through RPE specific conditional mutagenesis of Dicer1 or DGCR8, the importance of miRNA for RPE differentiation was uncovered. Interestingly, miRNAs were found to be dispensable for maintaining the RPE fate and survival, and yet they are essential for acquisition of important RPE properties such as the expression of genes involved in the visual cycle pathway, pigmentation and cell adhesion. Importantly miRNAs of the RPE were found to be required for maturation of the adjacent photoreceptors, specifically for the morphogenesis of the outer segments. The profiles of miRNA and mRNA altered in the Dicer1 deficient RPE point to a key role of miR-204 in regulation of RPE differentiation program in vivo and uncovers the importance of additional novel RPE miRNAs. The study exposes the combined regulatory activity of miRNAs of the RPE, which is required for RPE differentiation and for the development of the adjacent neuroretina.
MicroRNAs are essential for differentiation of the retinal pigmented epithelium and maturation of adjacent photoreceptors.
Specimen part, Treatment
View SamplesThis is a comparative microarray analysis of LE-AP-2a mutants vs. wild-type P0 littermate lenses.
Cell autonomous roles for AP-2alpha in lens vesicle separation and maintenance of the lens epithelial cell phenotype.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Chromatin remodeling enzyme Brg1 is required for mouse lens fiber cell terminal differentiation and its denucleation.
Specimen part
View SamplesBackground: FGF signaling controls numerous processes during cell lineage specification, organogenesis and terminal differentiation. In lens, FGF signaling was implicated as the key pathway that controls lens fiber cell differentiation, but little is known about its full range and spectrum of regulated genes. Results: Herein, we employed rat lens epithelial explant system and performed RNA and microRNA expression profiling in cells induced to differentiate by FGF2. The primary data were collected at explants grown overnight in the presence of 5 ng/ml of FGF2, followed by a treatment with 100 ng/ml of FGF2 and collection of samples at 2, 4, 12 and 24 hours. Global analysis identified extensive FGF2-regulated cellular responses that were both independent and dependent on microRNAs (miRNAs). We identified a total number of 131 FGF2-regulated miRNAs. Forty-four of these microRNAs had at least two predicted and inversely regulated target RNA molecules. The genes regulated by the highest number of miRs include Nfib, Nfat5, c-Maf, Ets1 and N-Myc, all encoding DNA-binding transcription factors. Analysis of RNA data revealed that activated FGF signaling influenced other major signaling pathways known to regulate lens differentiation including BMP/TGF-, Notch, and Wnt signaling. In the early response phase (2-4 hours), miRNAs targeted expression of batteries of genes that control transcription, cell death, cell proliferation, cell junction, and protein serine/threonine kinase activity. In late stages (12-24 hours), the main miRNA targets included regulators of cell cycle arrest and cellular differentiation. Specific miRNA:mRNA interaction networks were identified for c-Maf, N-Myc, and Nfib (DNA-binding transcription factors); Cnot6, Dicer1, Fbx33 and Wdr47 (RNA processing); Ash1l, Med1/PBP and Kdm5b (chromatin remodeling); and c-Maf, Ets1 and Stc1 (FGF signaling). MicroRNAs including miR-9, -143, -155, -455 and -543 downregulated expression of c-Maf in the 3-UTR luciferase reporter asssays. The functional requirement for miRNAs in lens was further demonstrated via disrupted lens fiber cell differentiation in lenses with inactivated Dicer1. Conclusions: These studies demonstrate for the first time global impact of activated FGF signaling in lens cell culture system and identified novel gene regulatory networks (GRNs) connected by multiple miRNAs.
Identification and characterization of FGF2-dependent mRNA: microRNA networks during lens fiber cell differentiation.
Specimen part
View SamplesGenome-wide approach to identify the cell-autonomous role of Brg1 in lens fiber cell terminal differentiation.
Chromatin remodeling enzyme Brg1 is required for mouse lens fiber cell terminal differentiation and its denucleation.
Specimen part
View SamplesDifferential expression of HSF4 in null newborn mouse and wildtype lenses was examined to identify putative downstream targets of HSF4.
Chromatin remodeling enzyme Brg1 is required for mouse lens fiber cell terminal differentiation and its denucleation.
Specimen part
View SamplesGenome-wide approach to identify the cell-autonomous role of Brg1 in lens fiber cell terminal differentiation.
Chromatin remodeling enzyme Brg1 is required for mouse lens fiber cell terminal differentiation and its denucleation.
Specimen part
View Samples