Molecular Mechanisms of Retinal Determination Proteins

描述(由申请人提供)：视网膜决定途径是在苍蝇眼发育的背景下首次描述的遗传级联。关于这一途径的大部分已知知识来自于遗传和进化研究。我们已经参与破译了RD途径的蛋白质组分，眼睛缺失(EYA)、腊肠(DACH)和Six在细胞命运决定中起中介作用的分子机制。目前的建议集中在眼睛缺失的蛋白质上，我们已经证明这些蛋白质除了具有转录激活功能外，还是蛋白质酪氨酸磷酸酶。在果蝇中，这种活动有助于眼睛的发育。然而，已知的Eya突变小鼠的表型表明，Eya在脊椎动物眼睛发育中可能不起到类似的作用。在最近的工作中，我们已经将EYAS的酪氨酸磷酸酶活性与细胞迁移和侵袭联系起来。已知有更多的EYA基因在神经脊起源的细胞中表达，报道的Eya1-/-小鼠的解剖缺陷与神经脊迁移的缺陷是一致的。因此，我们的初步数据提出了一个新的假设，即眼睛缺失的蛋白质促进了细胞的运动性和侵袭性过程，这在神经脊和眼睛的发育中发挥了作用。这一应用旨在利用体外细胞培养方法以及对小鼠靶向eya缺失的体内分析，破译由眼睛缺失蛋白调控的信号通路。了解眼眶功能的机制可能会导致对其在眼睛发育中的作用的新的见解，了解眼眶在继发性白内障和糖尿病视网膜病变等眼科疾病的发展中的潜在作用，以及癌症的发展和扩散。 与公共健康相关：EYA蛋白是参与胚胎眼发育的保守调控途径的一部分。尽管对苍蝇和老鼠进行了广泛的遗传分析，但EYA蛋白在脊椎动物眼睛发育中的确切作用仍然是个谜。我们已经证明，EYA蛋白既是酪氨酸磷酸酶，也是转录激活因子。此外，我们还发现，磷酸酶活性促进了细胞的迁移和侵袭。在此基础上，我们提出眼球在神经脊源性眼球结构的发育中起作用。在体外和体内分析了眼球运动可以影响细胞的运动和神经脊源性眼球结构发育的分子机制。这些研究的结果可以为脊椎动物眼睛的发育过程提供重要的洞察，以及EYA错误调节可能促进眼睛疾病和癌症的机制。

DESCRIPTION (provided by applicant): The Retinal Determination pathway is a genetic cascade that was first described in the context of fly eye development. Much of what is known about this pathway comes from genetic and evolutionary studies. We have been involved in deciphering the molecular mechanisms by which the protein components of the RD pathway, Eyes Absent (EYA), Dachshund (DACH), and SIX, mediate their roles in cell-fate determination. The present proposal focuses on the Eyes Absent proteins, which we have shown to be protein tyrosine phosphatases in addition to their established transcriptional activation function. In flies, this activity contributes to eye development. However, the known phenotypes of Eya mutant mice suggest that EYAs may not play a comparable role in vertebrate eye development. In recent work we have correlated the tyrosine phosphatase activity of the EYAs with cell migration and invasion. Further EYAs are known to be expressed in cells of neural crest origin, and the anatomical defects reported for Eya1-/- mice are consistent with defects in neural crest migration. Thus our preliminary data suggests the novel hypothesis that the Eyes Absent proteins promote the cellular processes of motility and invasiveness that play a role in neural crest and eye development. This application is designed to decipher the signaling pathways that are regulated by the Eyes Absent proteins using in vitro cell culture methods as well as in vivo analysis of targeted Eya deletions in mice. An understanding of the mechanisms by which the EYAs function could potentially lead to new insights regarding their role in eye development, to an understanding of the potential role of EYAs in the development of eye diseases such as secondary cataracts and diabetic retinopathy, and to the development and spread of cancers. PUBLIC HEALTH RELEVANCE: The EYA proteins are part of a conserved regulatory pathway involved in embryonic eye development. Despite extensive genetic analyses in flies and mice the precise role of the EYA proteins in vertebrate eye development remains enigmatic. We have shown that the EYA proteins are both tyrosine phosphatases as well as transcriptional activators. Further we show that the phosphatase activity promotes cell migration and invasiveness. Based on this we propose that the EYAs play a role in the development of neural crest-derived ocular structures. In vitro and in vivo analyses of the molecular mechanisms by which the EYAs could affect both cell motility and the development of ocular structures of neural crest origin are proposed. The results from these studies could provide significant insight into the process of vertebrate eye development, as well as the mechanisms by which EYA mis-regulation could promote eye diseases and cancers.