Transcriptional regulation of retinal mitochondrial function and cell cycle

描述(申请人提供)：视网膜形成需要严格控制视网膜前体细胞(RPC)增殖和分化的平衡。放松对这一机制的管制往往会导致严重的神经发育障碍或癌症。我们的长期目标是阐明RPC细胞周期调控与神经元分化之间的转录机制。在这项提案中，实验将确定转录调节蛋白罗宁(Thap11)在视网膜形成中的作用。罗宁是新近发现的一种新的胚胎干细胞多能因子，可影响胚胎干细胞的增殖和生长。罗宁也在发育中的大脑和视网膜中表达，但它在这些组织中的作用尚不清楚。在初步的研究中，我们已经发现，罗宁突变体视网膜表型与Cyclin D1缺失的小鼠相似，从而暗示罗宁作为一种细胞周期的调节因子，从G1期向S期转变。然而，对罗宁视网膜晶片序列初步数据的分析表明，线粒体基因丰富，而不是细胞周期机制。最近，线粒体通过促进Cyclin E的活性和进入S期而成为苍蝇和啮齿动物从G1期向S期转变的关键调节因素。因此，我们推测罗宁通过直接调节线粒体正常功能所需的基因和促进S时相进入来影响视网膜色素上皮细胞周期。为了验证这一假设，我们组建了一个拥有不同专业知识的团队，以促进使用遗传功能丧失和功能获得实验、代谢图谱、活视网膜显微镜和基因组学的协同、多学科方法。在完成这项提议后，我们预计我们将识别出一种新的转录机制，将线粒体功能与RPC中的细胞周期进程结合起来。这种对多潜能、增殖性RPC转录调控的深入了解最终将为视网膜细胞替代治疗以及作用于线粒体生物能量学和细胞周期界面的新型抗癌药物靶点提供有效的策略。

DESCRIPTION (provided by applicant): Retinogenesis requires a tightly controlled balance of retinal progenitor cell (RPC) proliferation and differentiation. Deregulation of this mechanism often results in profound neuro-developmental disorders or cancer. Our long term goal is to elucidate the transcriptional mechanisms coupling RPC cell cycle regulation to neuronal differentiation. In this proposal, experiments will define the role of the transcriptional regulato Ronin (Thap11) in retinogenesis. Ronin was identified recently as a novel embryonic stem cell (ESC) pluripotency factor, influencing ESC proliferation and growth. Ronin is also expressed throughout the developing brain and retina, but its role in these tissues is unknown. In preliminary studies, we have found that Ronin mutant retinae phenocopy the Cyclin D1 null mice thereby implicating Ronin as a regulator of the cell cycle G1 to S-phase transition. However, analysis of preliminary Ronin retinal ChIP-seq data showed enrichment for mitochondrial genes rather than cell cycle machinery. Recently, mitochondria have emerged as critical regulators of the G1 to S-phase transition in both flies and rodents by promoting Cyclin E activity and entry into S-phase. Therefore, we hypothesize that Ronin influences the RPC cell cycle by directly regulating genes required for proper mitochondrial function and promotion of S-phase entry. To test this hypothesis, we have assembled a team with diverse expertise, to facilitate a synergistic, multi- disciplinary approach using genetic loss- and gain-of-function experiments, metabolic profiling, live retinal microscopy and genomics. Upon completion of this proposal, we expect that we will have identified a new transcriptional mechanism that couples mitochondrial function to cell cycle progression in RPCs. This deeper understanding of the transcriptional regulation of multipotent, proliferative RPCs will ultimately inform efficacious strategies for retinal cell replacement therapies as well as novel cancer drug targets functioning at the interface of mitochondrial bioenergetics and the cell cycle.