Otx2 ChIP-seq in the adult mouse Retinal Pigmented Epithelium (RPE) and neural retina
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ABSTRACT: Otx2 has been shown to be non cell autonomously required for photoreceptor cell survival in the adult mouse RPE. This study aims to identify Otx2 DNA binding profile in both RPE and neural retina to i) identify direct targets of Otx2 in the RPE ii) compare Otx2 binding profile in neural retina and RPE to unveil hidden functions in the neural retina. WT and GFP antibodies were used to perform two independent ChIP-seq experiments using Illumina GAIIx.
Project description:Otx2 has been shown to be non cell autonomously required for photoreceptor cell survival in the adult mouse RPE. This study aims to identify Otx2 DNA binding profile in both RPE and neural retina to i) identify direct targets of Otx2 in the RPE ii) compare Otx2 binding profile in neural retina and RPE to unveil hidden functions in the neural retina.
Project description:In the vertebrate retina, the Otx2 transcription factor plays a crucial role in the cell fate determination of both rod and cone photoreceptors. Otx2 conditional knockout (CKO) mice exhibited a total absence of rods and cones in the retina due to their cell fate conversion to amacrine-like cells. In order to investigate the entire transcriptome regulated by Otx2 in the developing retina, we performed microarray analysis on the Otx2 CKO retina. In order to clarify the molecular role of Otx2 in transcriptional regulation during development, we investigated the expression profile of the Otx2 CKO retina compared with that of the control retina with the genotype Otx2flox/flox;Crx-cre- using microarrays at two time points, P1 and P12.
Project description:The retinal pigment epithelium (RPE) exhibits a diverse range of plasticity across vertebrates and is a potential source of cells for the regeneration of retinal neurons. Embryonic amniotes possess a transitory ability to regenerate neural retina through the reprogramming of RPE cells in an FGF-dependent manner. Chicken RPE can regenerate neural retina at embryonic day 4 (E4) of development, but RPE neural competence is lost by embryonic day 5 (E5). To identify mechanisms that underlie loss of regenerative competence, we performed RNA and ATAC sequencing using E4 and E5 chicken RPE, as well as at both stages following retinectomy and FGF2 treatment. We find that genes associated with neural retina fate remain FGF2-inducible in the non-regenerative E5 RPE. Coinciding with fate restriction, RPE cells stably exit the cell cycle and dampen the expression of cell cycle progression genes normally expressed during regeneration, including E2F1. E5 RPE exhibits progressive activation of gene pathways associated with mature function independently of retinectomy or FGF2 treatment, including retinal metabolism, pigmentation synthesis, and ion transport. Moreover, the E5 RPE fails to efficiently repress OTX2 expression in response to FGF2. Predicted OTX2 binding motifs undergo robust accessibility increases in E5 RPE, many of which coincide with putative regulatory elements for genes known to facilitate RPE differentiation and maturation. Together, these results uncover widespread alterations in gene regulation that culminate in the loss of RPE neural competence and implicate OTX2 as a key determinant in solidifying the RPE fate. These results yield valuable insight to the basis of RPE lineage restriction during early development and will be of importance in understanding the varying capacities for RPE-derived retinal regeneration observed among vertebrates.
Project description:The retinal pigment epithelium (RPE) exhibits a diverse range of plasticity across vertebrates and is a potential source of cells for the regeneration of retinal neurons. Embryonic amniotes possess a transitory ability to regenerate neural retina through the reprogramming of RPE cells in an FGF-dependent manner. Chicken RPE can regenerate neural retina at embryonic day 4 (E4) of development, but RPE neural competence is lost by embryonic day 5 (E5). To identify mechanisms that underlie loss of regenerative competence, we performed RNA and ATAC sequencing using E4 and E5 chicken RPE, as well as at both stages following retinectomy and FGF2 treatment. We find that genes associated with neural retina fate remain FGF2-inducible in the non-regenerative E5 RPE. Coinciding with fate restriction, RPE cells stably exit the cell cycle and dampen the expression of cell cycle progression genes normally expressed during regeneration, including E2F1. E5 RPE exhibits progressive activation of gene pathways associated with mature function independently of retinectomy or FGF2 treatment, including retinal metabolism, pigmentation synthesis, and ion transport. Moreover, the E5 RPE fails to efficiently repress OTX2 expression in response to FGF2. Predicted OTX2 binding motifs undergo robust accessibility increases in E5 RPE, many of which coincide with putative regulatory elements for genes known to facilitate RPE differentiation and maturation. Together, these results uncover widespread alterations in gene regulation that culminate in the loss of RPE neural competence and implicate OTX2 as a key determinant in solidifying the RPE fate. These results yield valuable insight to the basis of RPE lineage restriction during early development and will be of importance in understanding the varying capacities for RPE-derived retinal regeneration observed among vertebrates.
Project description:In the vertebrate retina, the Otx2 transcription factor plays a crucial role in the cell fate determination of both rod and cone photoreceptors. Otx2 conditional knockout (CKO) mice exhibited a total absence of rods and cones in the retina due to their cell fate conversion to amacrine-like cells. In order to investigate the entire transcriptome regulated by Otx2 in the developing retina, we performed microarray analysis on the Otx2 CKO retina.
Project description:To analyze the expression profile in the Otx2 knock-in (a knock-in mouse line expressing Otx2 from the Crx locus on chromosome 7) and Crx knockout retina, we performed a microarray analysis using wild-type (Crx +/+), Otx2 KI (Crx Otx2/Otx2) and Crx KO (Crx -/-) retina at P12.
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.
Project description:Leber congenital amaurosis (LCA) includes congenital or early-onset blinding diseases, characterized by vision loss together with nystagmus and nonrecordable electroretinogram (ERG). At least 19 genes are associated with LCA. While most LCA is recessive, mutations in the homeodomain transcription factor gene CRX lead to autosomal dominant LCA. The mechanism of CRX-LCA is not understood. Here, we report a new spontaneous mouse mutant carrying a frameshift mutation in Crx (CrxRip). We show that, unlike Crx-/- mouse retina, the dominant Crx c.763del1 mutation in CrxRip results in congenital blindness with complete loss of ERG, yet the photoreceptors do not degenerate. Dominant CRX frameshift mutations associated with LCA mimic the CrxRip phenotype that can be rescued by Crx. RNA-Seq profiling reveals progressive and complete loss of rod differentiation factor Nrl in CrxRip, while residual Nrl remains in Crx-/- retina. Moreover, Nrl partially restores the rod phenotype in CrxRip/+ mice. We show that the binding of Otx2 to Nrl promoter is obliterated in CrxRip mutant, and ectopic Otx2 can rescue the rod phenotype. Therefore, Otx2 is required to maintain Nrl expression in developing rods to consolidate rod fate. Our studies provide the mechanism of congenital blindness caused by dominant CRX mutations and should assist in therapeutic design. Retinal samples were harvested from WT, CrxRip/+, CrxRip/Rip, Crx-/- and Nrl-/- retina at postnatal days 2 and 21 for whole transcriptome sequencing (RNAseq). Each sample included 2 independent frozen retina and experiments were performed in duplicates. RNA-seq transcriptome libraries were constructed from 1 ?g of total RNA.
Project description:Medulloblastoma (MB) is the most common malignant primary pediatric brain tumor and is currently divided into 4 subtypes based on different genomic alterations, gene expression profiles and response to treatment: WNT, Sonic Hedgehog (SHH), Group 3 and Group 4. The extensive heterogeneity has made it difficult to assess the relevance of genes to malignant progression. For example, expression of the transcription factor, OTX2, is frequently dysregulated in multiple MB variants; however, it's role may be subtype specific. Here, we utilized human embryonic stem cell-derived neural precursors to determine the role of OTX2 in MB tumor progression using gain and loss of function studies. We used global gene expression profiling to determine what transcripts and pathways were differentially expressed following overexpression of OTX2 in human embryonic neural precursor cells. OTX2 was stably overexpressed in human embyronic neural precursors (hEN) by lentiviral transduction. OTX2-hENs and control hENs were then grown as neurospheres in defined medium and collected at passage 2. RNA was extracted using the Norgen All-in-One kit.