Mechanism of Action of Retinal Determination Proteins

描述(申请人提供)：近年来，很明显，决定细胞命运的遗传网络在不同物种之间是保守的。有趣的是，这些调节盒也被部署在多种发育环境中，例如在不同器官的形态发生中。这方面的一个很好的例子是最初在苍蝇眼发育中描述的盲眼缺失-正弦眼球-腊肠级联，被称为视网膜决定通路。脊椎动物的眼睛和肌肉发育也涉及到类似的途径，而该网络的组成部分也与大脑、耳朵和肾脏的发育有关。这些基因的突变与几种人类发育疾病有关，包括支气管炎肾综合征和先天性白内障(眼睛缺失)、全前脑、双眼无房和垂体异常(人类正弦眼球基因突变)、虹膜缺乏症(Pax6突变，人类失眼的同源物)以及后遗多指A2型、智力低下和一种形式的Bardet-Biedel综合征(腊肠突变)。我们的长期目标是解开这些调控途径背后的分子机制。这项建议集中在这个网络中的两个新的蛋白质家族：眼睛缺失和腊肠。 我们最近获得的证据表明，眼睛缺失具有蛋白酪氨酸磷酸酶活性，腊肠犬含有DNA结合基序。这些意想不到的观察结果改变了现有的这两个关键视网膜决定蛋白的作用模型，也是本文提出的研究的基础。我们计划使用结晶学和生物化学的综合努力来破译早期胚胎发育中眼睛缺失和腊肠动作的分子机制。

DESCRIPTION (provided by applicant): In recent years it has become apparent that the genetic networks specifying cell-fate are conserved across species. Interestingly, these regulatory cassettes are also deployed in multiple developmental contexts, for example in the morphogenesis of different organs. An excellent example of this is the Eyeless - Eyes Absent - Sine oculis - Dachshund cascade originally described in fly eye development, and called the retinal determination pathway. An analogous pathway is involved in vertebrate eye and muscle development, and components of the network have been implicated in brain, ear, and kidney development. Mutations in these genes are associated with several human developmental diseases including bronchio-oto-renal syndrome and congenital cataracts (Eyes Absent), holoprosencephaly, bilateral anophtalmia and pituitary anomalies (mutations in the human sine oculis genes), aniridia (mutations in Pax6, the human homologoue of Eyeless), as well as postaxial polydactyly type A2, mental retardation, and a form of Bardet-Biedel syndrome (Dachshund mutations). It is our long-term goal to unravel the molecular mechanisms underlying these regulatory pathways. This proposal focuses on the two novel protein families in this network: Eyes Absent and Dachshund. We have recently obtained evidence that Eyes Absent has protein tyrosine phosphatase activity and that Dachshund contains a DNA-binding motif. These unexpected observations alter existing models for the roles of these two critical retinal determination proteins, and are the basis for the studies proposed here. We plan to use crystallography and biochemistry in an integrated effort to decipher the molecular mechanisms of Eyes Absent and Dachshund action during early embryonic development.