Molecular Biology of Retinal Development

描述（申请人提供）：该项目的长期目标是阐明脊椎动物视网膜中光感受器产生的分子调控。这一知识对于开发有效的基于干细胞的光感受器替代疗法是必不可少的。关于所涉及的基因的身份以及它们如何从其他选择中选择光感受器的命运，还需要了解很多。在之前的资助期内的研究发现，在ngn2->neuroD->RaxL的转录途径中，neuroD在光感受器分化中起着重要作用。在这一途径中，ngn2在多能祖细胞中起作用，其下游遗传靶点包括neuroD；neuroD诱导光感受器发育程序，包括同源盒基因RaxL的表达。在这个应用中，我们将测试光感受器生产在ngn2和neuroD之间的关键步骤中使用ngn1的假设。目的1检查ngn1是否在正确的位置和时间表达，从而成为引导祖细胞进入光感受器路径的主要基因。目的2研究ngn1是否明确地引导祖细胞进入光感受器路径，从而只导致光感受器的产生。目的3确定ngn1是否需要光感受器的产生。目的4阐述了在光感受器产生过程中ngn1与ngn2和neuroD的遗传关系。这些研究将采用分子生物学、细胞生物学、发育生物学和遗传学等一系列技术进行。该项目有望阐明控制光感受器生产的转录调控。此外，它具有临床意义。识别光感受器产生的关键遗传因素将使体外或体内光感受器的有效产生具有治疗目的的研究成为可能。这些研究是及时的，在这个时代对干细胞研究替代疗法的兴趣增加。

DESCRIPTION (provided by applicant): The long-term goal of this project is to elucidate the molecular regulation of photoreceptor production in the vertebrate retina. This knowledge is imperative to the development of effective stem cell-based photoreceptor replacement therapies. Much needs to be learned about the identities of the genes involved and how they contribute to the selection of the photoreceptor fate from among the other options. Studies during the previous funding period identified neuroD as an instrumental player in photoreceptor differentiation, in a transcriptional pathway of ngn2->neuroD->RaxL. In this pathway, ngn2 functions in multipotent progenitors and its downstream genetic targets include neuroD; neuroD elicits a photoreceptor development program, including the expression of homeobox gene RaxL. In this application we will test the hypothesis that photoreceptor production employs ngn1 at a key step between ngn2 and neuroD. Aim 1 examines whether ngn1 is expressed at the right place and the right time to be a major gene in leading progenitors to the photoreceptor path. Aim 2 investigates whether ngn1 expressly steers progenitors to the photoreceptor path and, thus, leads exclusively to photoreceptor production. Aim 3 determines whether ngn1 is required for photoreceptor production. Aim 4 addresses how ngn1 genetically relates to ngn2 and neuroD during photoreceptor production. These studies will be carried out with a battery of techniques from molecular biology, cell biology, developmental biology, and genetics. This project promises to shed light on the transcriptional regulation governing photoreceptor production. Furthermore, it bears clinical implications. The identification of key genetic players in photoreceptor production will capacitate efficient in vitro or in vivo photoreceptor generation for studies with therapeutic goals. These studies are timely in this era of heightened interest in stem cell research for replacement therapies.