LAMIN A PROGERIA MUTATIONS AND NUCLEAR FUNCTION

描述(申请人提供)：Hutchinson-Gilford Progeria综合征(HGPS)是一种罕见的人类疾病，具有过早衰老的特征，包括皮下脂肪丢失、皮肤皱纹、脱发、动脉硬化和关节活动困难。大约90%的早衰症患者早年就死于进行性动脉硬化。HGPS是由人层蛋白A(Hla)突变引起的，层蛋白A是核层的一种蛋白质成分。这项拟议研究的长期目标是确定人类白细胞抗原基因突变改变核功能从而导致这些过早衰老缺陷的分子基础。我们的假设是，核质层蛋白结构除了在板层中的结构外，还形成一个核骨架系统，为关键的核功能提供所需的基础设施，包括DNA复制、转录、染色质组织、核质运输和核的拆解、组装和形状。了解HGPS突变是如何改变这些功能的，将有助于揭示导致早衰症患者出现的多种与年龄相关的疾病的机制，包括心肌病和中风。为此，两个在层蛋白遗传学、结构、功能和核运输方面拥有相当专业知识的实验室将合作解决以下具体目标：1)通过协调使用生化和显微方法来表征HGPS基因突变对核结构和组织的影响。2)研究HGPS基因突变对核功能的影响：利用HGPS患者细胞和无细胞非洲爪蛙核标本进行DNA复制和细胞分裂。3)研究HGPS基因突变对核功能的影响：核进出口、核孔复合体结构和核膜通透性。4)使用人和动物细胞模型来测试人类白细胞抗原基因突变对HGP中受影响最大的间充质细胞类型的影响。这些集体研究将为人类白细胞抗原基因突变如何导致早衰症的缺陷提供重要的见解。

DESCRIPTION (provided by applicant): Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare human disease with characteristics of premature aging that include loss of subcutaneous fat, wrinkled skin, loss of hair, arteriosclerosis, and difficulty in moving joints. About 90% of progeria patients die at an early age from progressive arteriosclerosis. HGPS is caused by mutations in human lamin A (hLA), a protein component of the nuclear lamina. The long-term objective of the proposed research is to determine the molecular basis by which mutations in the hLA gene alter nuclear function to cause these premature aging defects. It is our hypothesis that nucleoplasmic lamin structures, in addition to those in the lamina, form a nucleoskeletal system that provides the infrastructure required for crucial nuclear functions, including DNA replication, transcription, chromatin organization, nucleocytoplasmic transport and nuclear disassembly, assembly and shape. Understanding how these functions are altered by HGPS mutations will shed light on the mechanisms responsible for the multiple age-related disorders seen in patients with progeria, including cardiomyopathies and strokes. To this end, two laboratories with considerable expertise in lamin genetics, structure, function and nuclear transport will collaborate to address the following specific aims: 1) Characterize the effects of HGPS hLA mutations on nuclear structure and organization by the coordinated use of biochemical and microscopic methods. 2) Characterize the effects of HGPS hLA mutations on nuclear functions: DNA replication and cell division using HGPS patient cells and cell-free preparations of Xenopus nuclei. 3) Characterize the effects of HGPS hLA mutations on nuclear functions: nuclear import and export, nuclear pore complex structure and nuclear envelope permeability. 4) The use of human and animal cell models to test the effects of hLA mutations on mesenchymal cell types most affected in HGPS. These collective studies will provide important insights into how hLA mutations cause the defects seen in progeria.