Project description:We profiled retinal progenitor cells by integrating next generation sequencing methods and interrogating changes in chromatin accessibility at embryonic and post-natal murine stages. We identified putative factors involved in the developmental progression of the retinal progenitors epigenome and we report Lhx2 role in the regulation of chromatin accessibility by coordinated action of developmentally regulated pioneer factors
Project description:Lhx2 is a retinal progenitor cell transcription factor critical for eye development. We previously reported that conditional inactivation of Lhx2 at the start of mouse retinal neurogenesis disrupted retinal progenitor cell (RPC) proliferation, greatly reduced the RPC pool and altered neurogenic output as indicated by changes in the production of multiple fated precursor populations. To identify genes whose expression levels are dependent on Lhx2 at this stage of development, Lhx2 conditional inactivation was initiated at E11.5 in RPCs with the progenitor Cre driver Hes1CreERT2 and retinal tissue was collected at E15.5 for RNA sequencing. The gene expression profiles of Lhx2 CKO retinas were compared to control (Lhx2 conditional heterozygotes) were compared. Downregulated and upregulated gene expression was observed, with some likely due to direct and indirect regulation by Lhx2 within RPCs and others due to changes in differentiation and the altered neurogenic output.
Project description:Transitions in competence underlie the ability of CNS progenitors to generate a diversity of neurons and glia. Retinal progenitor cells in mouse generate early-born cell types embryonically and late-born cell types largely postnatally. We find that the transition from early to late progenitor competence is regulated by Jarid2. Loss of Jarid2 results in extended production of early cell types and extended expression of early progenitor genes. Jarid2 can regulate histone modifications, and we find reduction of repressive mark H3K27me3 on a subset of early progenitor genes with loss of Jarid2, most notably Foxp1. We show that Foxp1 regulates the competence to generate early-born retinal cell types, promotes early and represses late progenitor gene expression, and is required for extending early retinal cell production after loss of Jarid2. We conclude Jarid2 facilitates progression of retinal progenitor temporal identity by repressing Foxp1, which is a primary regulator of early temporal patterning.
Project description:Transitions in competence underlie the ability of CNS progenitors to generate a diversity of neurons and glia. Retinal progenitor cells in mouse generate early-born cell types embryonically and late-born cell types largely postnatally. We find that the transition from early to late progenitor competence is regulated by Jarid2. Loss of Jarid2 results in extended production of early cell types and extended expression of early progenitor genes. Jarid2 can regulate histone modifications, and we find reduction of repressive mark H3K27me3 on a subset of early progenitor genes with loss of Jarid2, most notably Foxp1. We show that Foxp1 regulates the competence to generate early-born retinal cell types, promotes early and represses late progenitor gene expression, and is required for extending early retinal cell production after loss of Jarid2. We conclude Jarid2 facilitates progression of retinal progenitor temporal identity by repressing Foxp1, which is a primary regulator of early temporal patterning.
Project description:Transitions in competence underlie the ability of CNS progenitors to generate a diversity of neurons and glia. Retinal progenitor cells in mouse generate early-born cell types embryonically and late-born cell types largely postnatally. We find that the transition from early to late progenitor competence is regulated by Jarid2. Loss of Jarid2 results in extended production of early cell types and extended expression of early progenitor genes. Jarid2 can regulate histone modifications, and we find reduction of repressive mark H3K27me3 on a subset of early progenitor genes with loss of Jarid2, most notably Foxp1. We show that Foxp1 regulates the competence to generate early-born retinal cell types, promotes early and represses late progenitor gene expression, and is required for extending early retinal cell production after loss of Jarid2. We conclude Jarid2 facilitates progression of retinal progenitor temporal identity by repressing Foxp1, which is a primary regulator of early temporal patterning.
Project description:Transitions in competence underlie the ability of CNS progenitors to generate a diversity of neurons and glia. Retinal progenitor cells in mouse generate early-born cell types embryonically and late-born cell types largely postnatally. We find that the transition from early to late progenitor competence is regulated by Jarid2. Loss of Jarid2 results in extended production of early cell types and extended expression of early progenitor genes. Jarid2 can regulate histone modifications, and we find reduction of repressive mark H3K27me3 on a subset of early progenitor genes with loss of Jarid2, most notably Foxp1. We show that Foxp1 regulates the competence to generate early-born retinal cell types, promotes early and represses late progenitor gene expression, and is required for extending early retinal cell production after loss of Jarid2. We conclude Jarid2 facilitates progression of retinal progenitor temporal identity by repressing Foxp1, which is a primary regulator of early temporal patterning.
Project description:Transitions in competence underlie the ability of CNS progenitors to generate a diversity of neurons and glia. Retinal progenitor cells in mouse generate early-born cell types embryonically and late-born cell types largely postnatally. We find that the transition from early to late progenitor competence is regulated by Jarid2. Loss of Jarid2 results in extended production of early cell types and extended expression of early progenitor genes. Jarid2 can regulate histone modifications, and we find reduction of repressive mark H3K27me3 on a subset of early progenitor genes with loss of Jarid2, most notably Foxp1. We show that Foxp1 regulates the competence to generate early-born retinal cell types, promotes early and represses late progenitor gene expression, and is required for extending early retinal cell production after loss of Jarid2. We conclude Jarid2 facilitates progression of retinal progenitor temporal identity by repressing Foxp1, which is a primary regulator of early temporal patterning.
Project description:The histone methyltransferase complex PRC2 controls key steps in developmental transitions and cell fate choices. However, its roles in vertebrate eye development remain unknown. Here we report that in Xenopus PRC2 regulates the progression of retinal progenitors from proliferation to differentiation. We show that the PRC2 core components are enriched in retinal progenitors and downregulated with differentiation. Knockdown of the PRC2 core component Ezh2 leads to reduced retinal progenitor proliferation in part due to upregulation of the cdk inhibitor p15Ink4b. In addition, while PRC2 knockdown does not alter eye patterning, retinal progenitor gene expression or expression of the neural competence factor Sox2, it does cause suppression of proneural bHLH gene expression, indicating that PRC2 is critical for the initiation of neural differentiation in the retina. Consistent with this, knocking down or blocking PRC2 function constrains the generation of most retinal neural cell types and promotes a Mueller glial cell fate decision. We also show that Wnt/β-catenin signaling acting through the receptor Frizzled 5, but independent of Sox2, regulates expression of key PRC2 subunits in the developing retina. This is consistent with a role for this pathway in coordinating proliferation and the transition to neurogenesis in the Xenopus retina. Our data establishes PRC2 as a regulator of proliferation and differentiation during eye development.
Project description:The histone methyltransferase complex PRC2 controls key steps in developmental transitions and cell fate choices. However, its roles in vertebrate eye development remain unknown. Here we report that in Xenopus PRC2 regulates the progression of retinal progenitors from proliferation to differentiation. We show that the PRC2 core components are enriched in retinal progenitors and downregulated with differentiation. Knockdown of the PRC2 core component Ezh2 leads to reduced retinal progenitor proliferation in part due to upregulation of the cdk inhibitor p15Ink4b. In addition, while PRC2 knockdown does not alter eye patterning, retinal progenitor gene expression or expression of the neural competence factor Sox2, it does cause suppression of proneural bHLH gene expression, indicating that PRC2 is critical for the initiation of neural differentiation in the retina. Consistent with this, knocking down or blocking PRC2 function constrains the generation of most retinal neural cell types and promotes a Mueller glial cell fate decision. We also show that Wnt/?-catenin signaling acting through the receptor Frizzled 5, but independent of Sox2, regulates expression of key PRC2 subunits in the developing retina. This is consistent with a role for this pathway in coordinating proliferation and the transition to neurogenesis in the Xenopus retina. Our data establishes PRC2 as a regulator of proliferation and differentiation during eye development. Xenopus embryos were injected at the 8-cell stage with 5ng Ezh2 ATG MO or 5ng control MO (scrambled sequence of Ezh2 ATG MO) together with 400 pg mRNA for GFP as a lineage tracer. At stage 27, GFP-positive eyes were isolated by microdissection. Pools of 20-25 eyes were used to prepare total RNA for each sample on the microarray. 4 control and 4 Ezh2 ATG MO samples were hybridized to Agilent 1-color microarrays.
Project description:Tissue-specific transcription factors control the transcriptome through an association with noncoding regulatory regions (cistromes). Identifying the combination of transcription factors that dictate specific cell fate, their specific cistromes and examining their involvement in complex human traits remain a major challenge. Here we focus on the retinal pigmented epithelium (RPE), an essential lineage for retinal development and function and the primary tissue affected in age-related macular degeneration (AMD), a leading cause of blindness. By combining mechanistic findings in stem-cell-derived human RPE, in- vivo functional studies in mice and global transcriptomic and proteomic analyses, we revealed that the key developmental transcription factors LHX2 and OTX2 function together in transcriptional module containing LDB1 and SWI/SNF (BAF) to regulate the RPE transcriptome. Importantly, the intersection between the identified LHX2-OTX2 cistrome with published expression quantitative trait loci, ATAC-seq data from human RPE, and AMD GWAS data, followed by functional validation using a reporter assay, revealed a causal genetic variant that affects AMD risk by altering TRPM1 expression in the RPE through modulation of LHX2 transcriptional activity on its promoter. Taken together, the reported cistrome of LHX2 and OTX2, the identified downstream genes and interacting co-factors reveal the RPE transcription module and uncover a causal regulatory risk SNP in the multifactorial common blinding disease AMD.