Molecular Mechanisms of Retinal Determination Proteins

描述（由申请人提供）：视网膜决定途径是一个遗传级联，首次在苍蝇眼睛发育的背景下被描述。我们对这一途径的了解大多来自遗传和进化研究。我们已经参与破译RD途径的蛋白质成分，Eyes Absent (EYA), Dachshund （DACH）和SIX在细胞命运决定中的作用的分子机制。目前的建议集中在Eyes Absent蛋白上，我们已经证明除了具有既定的转录激活功能外，它还是蛋白酪氨酸磷酸酶。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，EYAs可能在脊椎动物的眼睛发育中不起类似的作用。在最近的工作中，我们将EYAs的酪氨酸磷酸酶活性与细胞迁移和侵袭联系起来。进一步的EYAs已知在神经嵴起源的细胞中表达，并且Eya1-/-小鼠的解剖缺陷与神经嵴迁移缺陷一致。因此，我们的初步数据提出了新的假设，即眼睛缺失蛋白促进了在神经嵴和眼睛发育中发挥作用的运动和侵袭性细胞过程。该应用程序旨在通过体外细胞培养方法以及小鼠靶向Eya缺失的体内分析来破译由Eyes Absent蛋白调节的信号通路。对EYAs功能机制的理解可能会导致对其在眼睛发育中的作用的新见解，以及对EYAs在继发性白内障和糖尿病视网膜病变等眼病发展中的潜在作用的理解，以及对癌症发展和扩散的理解。

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.