RX HOMEOBOX GENE AND RETINAL FORMATION

脊椎动物的眼睛形成是一个复杂的过程，需要 前神经板的规格，前神经板的形成 与晶状体和晶状体的细胞分化 视网膜。这些发育过程中的每一个都可能是 由转录调控因子、生长调节因子的相互作用调节 因子及其受体。这项研究的目标是 确定在基因和过程中起关键作用的基因和过程 眼睛形成的初始阶段。具体的重点将是 放在同源异型盒基因Rx的形成中的作用 视网膜祖细胞与视网膜干细胞的维持 细胞。我们发现Rx对于正常的眼睛是必不可少的 发展及其错误表达对眼睛有深远的影响 形态学。注射Rx RNA的非洲爪哇胚胎发育异位 视网膜组织，表现为神经视网膜过度增殖。 携带该基因零等位基因的小鼠胚胎不会形成 视杯，因此不会发育成眼睛。考虑到至关重要的 Rx在眼睛发育过程中的作用，我们提出了三个具体的 在视网膜形成过程中与其功能相关的目标： 具体目标1：研究Rx调控途径。这将是 通过分析非洲爪哇胚胎中的基因表达和 注射Rx RNA的动物帽子及其基因表达分析 在Rx空小鼠突变体中。具体目标2：确定 将Rx表达定向到视网膜前体细胞的序列 细胞和视网膜干细胞。为此，我们将结扎 Rx基因5‘侧翼区对β-半乳糖苷酶的作用 记者制度。使用这种结构制成的转基因小鼠将 监测眼睛特异表达的β-半乳糖苷酶。 具体目标3：视网膜干细胞永生化。视网膜 干细胞将通过融合Rx调控因子而永生化 序列与SV40T抗原或通过连接Rx编码序列 到一个结构性激活的启动子。 这一研究对于更好地理解常态具有重要意义 和异常的眼睛发育，如无眼症和 小眼炎，很可能为我们提供信息 变性眼球内视网膜细胞置换的必要性 疾病使用视网膜干细胞群体。

Vertebrate eye formation is a complex process that requires specification of the anterior neural plate, formation of the optic vesicle, and cellular differentiation of the lens and retina. Each of these developmental processes is likely to be mediated by an interaction of transcriptional regulators, growth factors and their receptors. It is the goal of this research to identify genes and processes that play a critical role in the initial stages of eye formation. Specific emphasis will be placed on the role of the homeobox gene Rx in the formation of retinal progenitor cells and in the maintenance of retinal stem cells. We have found that Rx is essential for normal eye development and its misexpression has profound effects on eye morphology. Xenopus embryos injected with Rx RNA develop ectopic retinal tissue and display hyperproliferation in the neuroretina. Mouse embryos carrying a null allele of this gene do not form optic cups and consequently do not develop eyes. Given the vital role of Rx during eye development, we propose three specific goals related to its function during retinal formation: Specific aim 1: Study of the Rx regulatory pathway. This will be achieved by analyzing gene expression in Xenopus embryos and animal caps injected with Rx RNA and by analyzing gene expression in Rx null mouse mutant. Specific aim 2: Characterization of sequences that direct Rx expression into the retinal progenitor cells and retinal stem cells. For this purpose we will ligate the 5' flanking regions of the Rx gene to Beta-galactosidase reporter system. Transgenic mice made using this construct will be monitored for eye specific expression of Beta-galactosidase. Specific aim 3: Immortalization of retinal stem cells. Retinal stem cells will be immortalized either by fusing Rx regulatory sequences to the SV40 T antigen or by linking Rx coding sequences to a constitutively activated promoter. This research is of importance for better understanding of normal and abnormal eye development such as anophthalmia and microphthalmia, and is likely to provide us with information necessary for replacement of retinal cells in degenerative eye diseases using retinal stem cell population.