Epigenetic Regulation of Retinal Development by BCOR

项目摘要 正常视力取决于主要视网膜细胞类型的平衡生成和稳态调节， 这些过程的中断可能导致先天性视网膜疾病和视网膜变性， 全世界每年有数百万人死亡。再生医学依赖于我们对视网膜 用于告知视网膜细胞重编程和制造的开发。虽然有重大的 在解开转录因子的作用的进展，一个主要的差距存在于我们的知识如何这些 严格调控的基因网络由表观遗传机制控制。多梳群配合物是 进化上保守的表观遗传机制，通过组蛋白修饰重塑染色质， 沉默靶向基因，最近已显示影响视网膜神经发生和谱系决定。 BCOR是Polycomb抑制复合物1变体的一个组分，其泛素化组蛋白上的赖氨酸119 H2A（H2AK119Ub）。BCOR失调明显与眼部和视网膜疾病相关，包括伦茨 小眼症、眼面心齿综合征和视网膜母细胞瘤，但它在视网膜神经发生中的作用是 仍然没有很好地理解。在初步研究中，我进行了免疫共沉淀-质谱分析， 验证了BCOR与视网膜细胞中其他PcG蛋白的相互作用。然后我用BCOR染色质 免疫沉淀测序（ChIP-seq），并在视网膜祖细胞基因LHX 2处鉴定出强峰， PAX 6、SIX 3和SIX 6，它们都在视泡发育中起重要作用，并且后来在视泡发育中发挥不同的作用。 视网膜细胞的命运决定。因此，我建议研究BCOR在视网膜神经发生中的作用。我 假设BCOR通过募集细胞来介导从视网膜祖细胞到分化细胞类型的转换 PcG蛋白调节染色质上的H2 AK 119 Ub以抑制多能性基因。我来测试一下 目的：（1）明确BCOR调节视网膜神经元凋亡的表观遗传机制， 祖细胞基因，和（2）确定BCOR如何影响体内主要视网膜细胞类型的产生。我 总体目标是表征BCOR-ncPRC 1.1在视网膜发育中的作用， 视网膜再生策略的新表观遗传靶点。

Project Summary Normal vision depends on the balanced generation and homeostatic regulation of major retinal cell types, and the disruption of these processes may result in congenital retinal disorders and retinal degeneration, affecting millions of people around the world each year. Regenerative medicine depends on our understanding of retinal development for informing retinal cell reprogramming and manufacturing. While there have been significant advances in unravelling the roles of transcription factors, a major gap exists in our knowledge of how these tightly regulated gene networks are governed by epigenetic mechanisms. Polycomb-group complexes are evolutionarily conserved epigenetic machineries that remodel chromatin through histone modifications for silencing targeted genes and have been recently shown to affect retinal neurogenesis and lineage decisions. BCOR is a component of the Polycomb Repressive Complex 1 variant that ubiquitinates lysine 119 on histone H2A (H2AK119Ub). Dysregulation of BCOR is clearly associated with eye and retinal disorders, including Lenz microphthalmia, Oculofaciocardiodental Syndrome, and retinoblastoma, but its role in retinal neurogenesis is still not well understood. In preliminary studies, I performed coimmunoprecipitation-mass spectrometry and validated BCOR’s interaction with other PcG proteins in retinal cells. I then performed BCOR chromatin immunoprecipitation sequencing (ChIP-seq) and identified strong peaks at retinal progenitor genes LHX2, PAX6, SIX3, and SIX6, all of which are significant in optic vesicle development and later play distinct roles in retinal cell fate decisions. Thus, I propose to investigate the role of BCOR in retinal neurogenesis. I hypothesize that BCOR mediates the switch from retinal progenitors to differentiated cell types by recruiting PcG proteins to regulate H2AK119Ub on the chromatin to repress multipotency genes. I will test this hypothesis with the following aims: (1) Identify the epigenetic mechanism of BCOR for regulating retinal progenitor genes, and (2) Determine how BCOR affects the generation of major retinal cell types in vivo. My overall objective is to characterize BCOR-ncPRC1.1’s role in retinal development as an avenue to discovering new epigenetic targets for regenerative strategies in the retina.