Genetic Analysis of Snail Superfamily Genes in Mice

描述（由申请人提供）：蜗牛超家族基因编码含有锌指的DNA结合蛋白，作为转录抑制因子。这个超家族有两个主要分支：蜗牛家族（由Snai1、2和3基因编码）和Scratch家族（由Scrt1和2基因编码）。这些蛋白是上皮-间质转化的关键调节因子，也在细胞增殖、存活和运动中发挥作用。我们对小鼠胚胎发育过程中蜗牛超家族基因的需求进行了全面的遗传分析。我们在之前的资助期间的工作建立了所有这些基因的零表型，并证明在Snai1突变体中观察到最严重的胚胎表型。然而，关于蜗牛超家族基因的需求和作用仍然存在许多问题。在本研究中，我们将利用分子和遗传学的方法来分析蜗牛家族基因在小鼠胚胎发生过程中所起的作用，并了解导致突变表型的机制。我们已经产生的突变小鼠菌株，以及我们将构建的突变菌株，构成了一套独特的试剂，使我们能够精细地解剖蜗牛家族基因在胚胎发育过程中的作用。本研究的具体目的是：1)确定小鼠早期胚胎发生过程中SNAI1蛋白转录抑制的靶点；2)在体内验证gsk3 β激酶和betaTrcp泛素连接酶对SNAI1蛋白的翻译后调控是SNAI1功能的必要条件；3)通过确定Snai1、Snai2和Snai3基因在肌肉发育、生理和再生过程中的个体作用，验证蜗牛家族基因在肌肉发育、生理和再生过程中起重要作用的假设；4)评估Snai3与Snai2和Snai1在肌肉发育、生理和再生过程中的冗余性。

DESCRIPTION (provided by applicant): Snail superfamily genes encode zinc finger-containing DNA binding proteins that act as transcriptional repressors. This superfamily has two main branches: the Snail family (encoded by the Snai1, 2 and 3 genes) and the Scratch family (the Scrt1 and 2 genes). These proteins are key regulators of the epithelial- mesenchymal transition, and also play roles in cell proliferation, survival and movement. We have performed a comprehensive genetic analysis of the requirements for Snail superfamily genes during embryonic development in mice. Our work during the prior funding periods of this grant established the null phenotype of all of these genes, and demonstrated that the most severe embryonic phenotype is observed in Snai1 mutants. However, many questions remain about the requirements and roles of Snail superfamily genes. In this proposal, both molecular and genetic approaches will be utilized to analyze the roles played by Snail family genes during embryogenesis in mice, and to understand the mechanisms causing the mutant phenotypes. The mutant mouse strains we have already generated, as well as the mutant strains we will construct as part of this proposal, constitute a unique set of reagents that will permit us to finely dissect the roles of Snail family genes during embryonic development. The specific aims of this proposal are: 1) determine targets for transcriptional repression by the SNAI1 protein during early embryogenesis in mice; 2) test the hypothesis that post- translational regulation of SNAI1 protein by the GSK3beta kinase and the betaTrcp ubiquitin ligase are essential for Snai1 function in vivo; 3) test the hypothesis that Snail family genes are important for muscle development, physiology and regeneration by determining the individual roles of the Snai1, Snai2 and Snai3 genes in these processes; 4) assess Snai3 redundancy with Snai2 and Snai1 function during muscle development, physiology and regeneration. Public Health Relevance: The long-term goal of this proposal is to understand the roles that Snail superfamily genes play during embryonic development in mammals. Snail superfamily genes encode zinc finger-containing DNA binding proteins that act as transcriptional repressors. The studies described in this proposal will further our understanding of the roles played by Snail superfamily genes during mammalian development, and will be relevant to the study of both normal and abnormal human development.