MOLECULAR CONTROL OF RETINAL STEM CELL DEVELOPMENT

细胞形成视网膜的承诺发生在胚胎发育的早期 因为神经板被区域化到特定的领域。一次 被指定为视网膜的前体细胞以干细胞的形式增殖 直到发出停止分裂和分化的信号。视网膜干 细胞是多能的，可以产生所有有色素的细胞 和神经视网膜，并能够参与视网膜 低等脊椎动物的再生。我们选择了研究可能的基因 控制视网膜干细胞的命运，以努力确定 控制建立和增殖的分子机制 视网膜上的。 几个含有同源异型盒的转录调控基因 在胚胎时期对眼睛的正常形成很重要 开发，包括Pax6、Chx10和LHX2。一个新的视网膜家族 同源异型盒基因Rx在空间和时间模式中表达 与视网膜干细胞规范中的角色一致 扩散。Rx基因的功能对正常的眼睛至关重要 形成，因为过度表达会导致神经过度增殖 视网膜和视网膜色素上皮，以及Rx的靶向缺失 小鼠体内的基因消除了视泡的形成，并导致 一只失眼的小老鼠出生。我们建议进行的研究旨在 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来 研究Rx在视网膜形成、增殖和生长中的作用 差异化。利用基因表达研究小鼠携带 不同的眼球突变，我们将调查是否有必要使用Rx 以获得视网膜细胞命运的初步说明。一种分析 晚期Rx在视网膜干细胞增殖和增殖中的作用 将使用分子技术在小学进行区分 小鼠视网膜培养和人视网膜母细胞瘤细胞。最后，我们 建议对无眼症患者的DNA样本进行突变筛查 在人类Rx基因中。这些实验将阐明 人眼发育中的RX同源框基因。拟议的研究包括 对我们对眼睛的基本理解的重要启示 器官发生，并可能有助于制定治疗策略 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.