INVESTIGATION OF MAMMALIAN RETINAL NEURON DEVELOPMENT

描述（由申请人提供）：哺乳动物视网膜的早期发育 通过一系列细胞变化进行， 有丝分裂，迁移到特定的层状位置，并最终分化 七种基本神经或神经胶质细胞类型之一。这些事件中的缺陷 导致人眼畸形，包括视神经发育不全或发育不全， 先天性青光眼和视锥/视杆营养不良综合征。的遗传控制 目前对这些事件了解甚少。然而，最近的研究结果表明， 控制某些发育过程的关键蛋白质是核蛋白 转录因子这项申请将使用胚胎学，遗传学， 免疫组化、组织学和分子生物学方法探讨其功能 小鼠的Math 5基因。Math 5编码一种基本的螺旋-环-螺旋转录 在视网膜祖细胞中的表达预示着终末 视网膜神经节细胞（RGC）的出生日期。在初步研究中， 创建了Math 5基因的靶向缺失并分析了产后情况 视网膜中的表型。Math 5-/-成年小鼠完全存活，但缺乏视觉 神经、交叉和RGC。视锥细胞的增加也是 观察本申请的目的是进一步研究 眼睛发育过程中的数学5。虽然出生后突变的眼睛不含RGCs， 我们已经观察到分化的显著减少，但不是完全丧失， 突变胚胎中的RGC。这些发现将进一步研究使用基因 表达研究和嵌合突变胚胎的创建， 聚集嵌合体产生。Math 5的一个新的表达域也被 在形成的视柄中被识别。这些视柄细胞的身份 Math 5在视柄发育过程中的潜在功能将是 研究了Math 5与其他眼模式的层次关系 形成（Pax 6，Hes 1，Pax 2，Chx 10）和视网膜神经元（Math 3，Mash 1，Ngn 2， NeuroD、Brn 3b、Isl-1）基因将通过基因表达进行探索， 突变分析Math 5基因组结构和序列的比较 而它的人类直系同源物Hath 5，证明了八个高度相关的基因的存在。 位于编码区5 ′和3 ′的保守基因组序列元件。 这些序列可能代表基因启动子和组织特异性表达 控制元件。在体外和体内实验将测试是否这些 序列调控Math 5基因表达。拟议的研究应产生 有价值的新的信息有关的发病机制的眼睛疾病， 为更好地诊断和预防这些疾病提供基础， 未来

DESCRIPTION (provided by applicant): Early development of the mammalian retina proceeds through a series of cellular changes in which progenitor cells exit mitosis, migrate to particular laminar positions and terminally differentiate into one of seven basic neural or glial cell types. Defects in these events lead to human eye malformations, including optic nerve aplasia or hypoplasia, congenital glaucoma and cone/rod dystrophic syndromes. The genetic control of these events is poorly understood at present. However, recent findings suggest that key proteins controlling some of these developmental processes are nuclear transcription factors. This application will use embryological, genetic, immunohistochemical, histological and molecular methods to explore the function of the mouse Math5 gene. Math5 encodes a basic helix-loop-helix transcription factor whose expression in retinal progenitors foreshadows the terminal birthdates of retinal ganglion cells (RGCs). In preliminary studies we have created a targeted deletion of the Math5 gene and analyzed the postnatal phenotypes in the retina. Math5 -/- adult mice are fully viable but lack optic nerves, chiasmata and RGCs. An increase in cone photoreceptor cells was also observed. The aims of this application will further investigate the role of Math5 during eye development. Although postnatal mutant eyes contain no RGCs, we have observed a great reduction, but not complete loss, of differentiating RGCs in mutant embryos. These findings will be further investigated using gene expression studies and the creation of chimeric mutant embryos through aggregation chimera production. A new expression domain for Math5 has also been identified in the forming optic stalk. The identity of these optic stalk cells and a potential function for Math5 during optic stalk development will be studied. The hierarchical relationships of Math5 and other eye pattern formation (Pax6, Hes1, Pax2, Chx10) and retinal neuron (Math3, Mash 1, Ngn2, NeuroD, Brn3b, Isl-1) genes will be explored through gene expression and mutational analyses. Comparison of the genomic structure and sequence of Math5 and its human orthologue, Hath5, demonstrates the presence of eight highly conserved genomic sequence elements located 5' and 3' to the coding region. These sequences may represent the gene promoter and tissue-specific expression control elements. In vitro and in vivo experiments will test whether these sequences regulate Math5 gene expression. The proposed studies should yield valuable new information concerning the pathogenesis of eye disease and may provide a foundation for better diagnosis and prevention of these diseases in the future.