The role of LEM domain proteins in nuclear function

描述(由申请人提供)： 摘要：核膜是位于核膜下的蛋白质网络，对染色体组织和基因调控起着重要作用。其中一类LEM蛋白共有一个~40个氨基酸的LEM结构域(LEM-D)，它与保守的染色质桥蛋白--屏障自整合因子(BAF)结合。编码LEM-D蛋白的基因突变会导致几种被称为椎板病的人类疾病，包括Emery-Dreifuss肌营养不良症、心肌病和骨密度失调。尽管相关的LEM-D蛋白广泛表达，但这些病理是有组织限制性的。新出现的数据表明，椎板病症是由于间充质干细胞群体的动态平衡缺陷引起的。我们的研究将确定LEM-D蛋白在果蝇中的功能，以阐明核层在发育过程中赋予组织特异性调控的作用。这些研究利用了我们对编码LEM-D蛋白的三个基因突变的遗传分离。我们的研究表明，果蝇LEM-D蛋白有独特的和重叠的发育需求，有证据表明年龄增强的表型和在间充质干细胞生态位的形态发生中的作用。在这项建议中，提出了三个目标。首先，我们将定义DBAF在发育过程中的要求，以了解这种染色质结合蛋白如何参与LEM-D蛋白的间期功能。其次，我们将确定如何使用LEM-D来建立这类板层蛋白的组织特异性功能。第三，我们将确定LEM-D蛋白如何在涉及生殖系干细胞生态位形态发生的关键调控途径中发挥作用。总之，这些研究阐明了BAF和LEM-D蛋白如何在NE中共同作用，以建立组织发育所需的不同核层功能。因此，这些研究将为人类椎板病的分子机制提供见解。 公共卫生相关性： 项目简介细胞核的完整性和组织取决于核层的功能，核层是核膜下的蛋白质网络。核板成分的变化会导致几种与组织限制性病理相关的人类疾病，如Emery-Dreifuss肌营养不良症、心肌疾病和骨密度紊乱，尽管在所有细胞中都发现了核板蛋白。利用遗传学和分子生物学的方法，我们将在果蝇中确定一类核膜蛋白LEM结构域的功能，为深入了解人类核膜疾病的发病机制提供依据。

DESCRIPTION (provided by applicant): Abstract: The nuclear lamina is a protein meshwork underneath the nuclear envelope (NE) that contributes to chromosome organization and gene regulation. One class of lamina proteins shares an ~40 amino acid LEM domain (LEM-D) that binds Barrier-to-Autointegration Factor (BAF), the conserved chromatin bridging protein. Mutations in genes encoding LEM-D proteins cause several human diseases known as laminopathies, including Emery-Dreifuss muscular dystrophy, cardio- myopathies and bone density disorders. These pathologies are tissue-restricted, even though the relevant LEM-D proteins are broadly expressed. Emerging data suggest that laminopathies arise from defects in homeostasis of mesenchymal stem cell populations. Our studies will define the function of LEM-D proteins in Drosophila to elucidate the role of the nuclear lamina in conferring tissue-specific regulation during development. These studies capitalize on our genetic isolation of mutations in three genes encoding LEM-D proteins. Our investigations have shown that the Drosophila LEM-D proteins have unique and overlapping developmental requirements, with evidence of age-enhanced phenotypes and a role in the morphogenesis of a mesenchymal stem cell niche. In this proposal, three aims are proposed. First, we will define requirements for dBAF during development, to understand how this chromatin binding protein contributes to the interphase functions of LEM-D proteins. Second, we will determine how the LEM-D is used to establish tissue- specific functions of this class of lamina proteins. Third, we will establish how LEM-D proteins contribute to critical regulatory pathways involved in the morphogenesis of the germline stem cell niche. Together, these investigations elucidate how BAF and LEM-D proteins work together in the NE to establish distinct nuclear lamina functions required for tissue development. As such, these studies will provide insights into molecular mechanisms of human laminopathies. PUBLIC HEALTH RELEVANCE: PROJECT NARRATIVE The integrity and organization of the nucleus depends upon the function of the nuclear lamina, a protein meshwork that underlies the nuclear envelope. Alterations in nuclear lamina components cause several human diseases that are associated with tissue-restricted pathology, such as Emery-Dreifuss muscular dystrophy, myocardial diseases and bone density disorders, even though nuclear lamina proteins are found in all cells. Using genetic and molecular approaches in Drosophila, we will determine the function of one class of nuclear lamina proteins, the LEM domain proteins to provide insights into mechanisms of human disease of the nuclear lamina.