INVESTIGATION OF MAMMALIAN RETINAL NEURON DEVELOPMENT

描述(申请人提供)：哺乳动物视网膜的早期发育 通过祖细胞退出的一系列细胞变化进行 有丝分裂，迁移到特定的板层位置并终末分化 转化为七种基本的神经或神经胶质细胞类型之一。这些事件中的缺陷 导致人类眼睛畸形，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。家蚕的遗传控制 目前，人们对这些事件知之甚少。然而，最近的研究结果表明， 控制其中一些发育过程的关键蛋白质是核 转录因子。该应用程序将使用胚胎学、遗传学、 免疫组织化学、组织学和分子生物学方法探讨其功能 小鼠的Math5基因。Math5编码一个基本的螺旋-环-螺旋转录 视网膜祖细胞表达预示终末期的因子 视网膜神经节细胞(RGC)的出生日期。在初步研究中，我们有 创建了Math5基因的定向删除并分析了出生后 视网膜的表型。Math5-/-成年小鼠完全存活，但缺乏视觉 神经、交叉和视网膜节细胞。视锥感光细胞的增加也是 观察到的。本申请的目的将进一步调查 Math5在眼睛发育过程中。尽管出生后突变的眼睛中没有RGC， 我们观察到，区分的情况大大减少，但并不是完全丧失。 突变胚胎中的RGC。这些发现将用基因进行进一步的研究。 表达研究和嵌合突变胚胎的建立 聚合嵌合体生产。Math5的一个新的表达结构域也已经被 在形成的视柄中识别。这些视柄细胞的身份 Math5在视柄发育过程中的一个潜在功能是 学习。Math5与其他眼图的等级关系 形成(Pax6，Hes1，Pax2，Chx10)和视网膜神经元(Math3，Mash 1，Ngn2， Neurod，Brn3b，ISL-1)基因将通过基因表达和 突变分析。Math5基因的基因组结构和序列比较 它的人类同源基因，Hath5，证明了8个高度存在 基因组序列元件位于编码区的5‘和3’端。 这些序列可能代表基因启动子和组织特异性表达 控制元素。体外和体内实验将测试这些 序列调控Math5基因的表达。拟议的研究应该会产生 关于眼病发病机制的有价值的新信息，并可能 为更好地诊断和预防这些疾病奠定了基础 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.