MOLECULAR CONTROL OF RETINAL STEM CELL DEVELOPMENT

细胞定型形成视网膜发生在早期胚胎发生期间 因为神经板被划分为特定的区域。 一旦 在特定成为视网膜时，前体细胞增殖为干细胞， 细胞直到发出信号停止分裂和分化。 视网膜干 细胞是多能的，产生色素沉着的所有细胞。 和神经视网膜，并能够参与视网膜 低等脊椎动物的再生 我们选择研究基因， 来控制视网膜干细胞的命运， 控制建立和增殖的分子机制 的视网膜。 几个含有同源框的转录调控基因是 在胚胎期眼睛的正常形成是很重要的 包括Pax6、Chx10和Lhx2。 一个新的视网膜色素家族 同源异型盒基因Rx以空间和时间模式表达 与视网膜干细胞特化中的作用一致， 增殖 Rx基因的功能对正常的眼睛至关重要 形成，因为过度表达导致神经细胞过度增殖， 视网膜和视网膜色素上皮，以及Rx的靶向缺失 小鼠中的基因消除了视泡的形成， 无眼小鼠幼崽的诞生。 我们建议的研究旨在 确定Rx调节早期哺乳动物眼睛的机制 发展 我们在不同的实验系统中设计了三种策略， 研究Rx在视网膜形成、增殖和分化过程中的作用 分化 利用基因表达研究， 不同的眼部突变，我们将研究Rx是否是必要的 用于视网膜细胞命运的初始规格。 分析 在视网膜干细胞增殖过程中的后期Rx功能， 将使用分子技术在原发性肿瘤中进行分化。 小鼠视网膜培养物和人视网膜母细胞瘤细胞。最后我们 我建议从无眼患者身上筛选DNA样本， 在人类Rx基因中。这些实验将阐明 Rx同源盒基因与人眼发育。 拟议的研究有 对我们基本理解眼的重要意义 器官形成，并可能有助于医疗策略， 视网膜母细胞瘤、视网膜变性和无眼症。

Commitment of cells to form a retina occurs during early embryogenesis as the neural plate is regionalized into specific domains. Once specified to become retina, the precursor cells proliferate as stem cells until signaled to stop dividing and differentiate. Retinal stem cells are multipotent, giving rise to all of the cells of the pigmented and neural retina, and are capable of participating in retinal regeneration in lower vertebrates. We have chosen to study genes likely to control retinal stem cell fate in an effort to determine the molecular mechanisms that control the establishment and proliferation of the retina. Several homeobox-containing trasncriptional regulatory genes are important for the proper formation of the eye during embryonic development, including Pax6, Chx10 and Lhx2. A new family of retinal homeobox genes, Rx, is expressed in a spatial and temporal pattern consistent with a role in retinal stem cell specification and proliferation. The function of the Rx gene is crucial for proper eye formation, as overexpression causes hyperproliferation of the neural retina and retinal pigment epithelium, and targeted deletion of the Rx gene in the mouse eliminates optic vesicle formation and results in the birth of eyeless mouse pups. Our proposed studies are aimed at identifying the mechanisms by which Rx regulates early mammalian eye development. We have designed three strategies in different experimental systems to study the role of Rx during retinal formation, proliferation and differentiation. Using gene expression studies in mice carrying different ocular mutations, we will investigate whether Rx is necessary for the initial specification of retinal cell fate. An analysis of later Rx function during retinal stem cell proliferation and differentiation will be performed using molecular techniques in primary mouse retinal cultures and human retinoblastoma cells. Finally, we propose to screen DNA samples from anophthalmic patients for mutations in the human Rx gene. These experiments will elucidate the role of the Rx homeobox gene in human eye development. The proposed studies have important implications for our basic understanding of ocular organogenesis, and may contribute to medical treatment strategies for retinoblastoma, retinal degeneration and anophthalmia.