Analysis of a novel regulator of vertebrate retinal neurogenesis

描述（由申请人提供）：许多先天性眼部疾病源于早期发育的改变，包括神经视网膜内祖细胞的增殖和分化，尽管在许多情况下，这些疾病的潜在机制尚不清楚。通过定义控制正常视网膜神经发生的机制，我们可以更好地了解这些过程在病理情况下是如何被破坏的。bHLH转录因子在视网膜神经发生中起着关键作用，但对它们如何控制视网膜神经元分化过程知之甚少。我们已经确定了一个新的基因，sbt1，它编码一种新的蛋白质，表达在非洲爪蟾神经系统的发展，这是受前神经bHLH活动。我们的初步结果表明，sbt1是一个重要的调节视网膜神经发生在非洲爪蟾。我们已经鉴定了该基因的小鼠直系同源物，并且表明它也在神经系统中表达，并且具有调节视网膜神经元分化的保守能力。在这里，我们提出了两个新的方向分析sbt1功能。在具体目标1中，我们将通过对sbt1表达进行详细分析，并确定其表达是否依赖于前神经bHLH因子，来启动对小鼠视网膜发育过程中sbt1的研究。在具体目标2中，我们将分析sbt1的亚细胞定位，并为这种新蛋白定义蛋白质伴侣。这个提议中的实验将为sbt1的深入遗传学研究提供概念框架，sbt1是一个新的令人兴奋的基因，似乎是发育中视网膜神经元分化的关键调节因子。一个长期的希望是，我们最终可能能够操纵视网膜干细胞或祖细胞的分化来治疗视网膜变性疾病。我们的工作将有助于这方面的努力，表征视网膜神经元分化和细胞命运规范的分子机制。

DESCRIPTION (provided by applicant): A number of congenital eye disorders stem from alterations in early development, including proliferation and differentiation of progenitors within the neural retina, although in many cases the mechanisms underlying these disorders is not understood. By defining the mechanisms controlling normal retinal neurogenesis, we may gain a better understanding of how these processes are disrupted in pathological situations. bHLH transcription factors play a pivotal role in retinal neurogenesis, but remarkably little is known about how they control the process of retinal neuron differentiation. We have identified a new gene, sbt1, which encodes a novel protein that is expressed in the developing Xenopus nervous system and which is regulated by proneural bHLH activity. Our preliminary results indicate that sbt1 is an essential regulator of retinal neurogenesis in Xenopus. We have identified a mouse ortholog of this gene, and showed that it is also expressed in the nervous system and has a conserved ability to regulate retinal neuron differentiation. Here we propose to develop two new directions for the analysis of sbt1 function. In Specific Aim 1 we will initiate a study of sbt1 during mouse retinal development by performing a detailed analysis of sbt1 expression, and determining whether its expression depends upon proneural bHLH factors. In Specific Aim 2 we will analyze subcellular localization of sbt1 and define protein partners for this novel protein. The experiments in this proposal will provide the conceptual framework for an in-depth genetic study of sbt1, a novel and exciting gene that appears to be a key regulator of neuronal differentiation in the developing retina. A long-term hope is that we may ultimately be able to manipulate the differentiation of retinal stem cells or progenitors to treat retinal degenerative diseases. Our work will contribute to this effort by characterizing the molecular mechanisms underlying retinal neuron differentiation and cell fate specification.