LAMIN A PROGERIA MUTATIONS AND NUCLEAR FUNCTION

描述（由申请人提供）：Hutchinson-Gilford早衰综合征（HGPS）是一种罕见的人类疾病，具有过早衰老的特征，包括皮下脂肪损失、皮肤皱纹、脱发、动脉硬化和关节活动困难。大约90%的早衰症患者死于进行性动脉硬化。HGPS是由人核纤层蛋白A（hLA）突变引起的，hLA是核纤层的蛋白组分。这项研究的长期目标是确定hLA基因突变改变核功能导致这些过早老化缺陷的分子基础。我们的假设是，核质核纤层蛋白结构，除了那些在层，形成一个核骨架系统，提供关键的核功能，包括DNA复制，转录，染色质组织，核质运输和核拆卸，组装和形状所需的基础设施。了解HGPS突变如何改变这些功能将有助于了解早衰症患者中出现的多种年龄相关疾病的机制，包括心肌病和中风。为此，两个在核纤层蛋白遗传学、结构、功能和核转运方面具有相当专业知识的实验室将合作解决以下具体目标：1）通过协调使用生物化学和显微镜方法来表征HGPS hLA突变对核结构和组织的影响。2)表征HGPS hLA突变对核功能的影响：使用HGPS患者细胞和非洲爪蟾细胞核的无细胞制备物进行DNA复制和细胞分裂。3)表征HGPS hLA突变对核功能的影响：核输入和输出、核孔复合体结构和核膜渗透性。4)使用人类和动物细胞模型来测试hLA突变对HGPS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hLA突变如何导致早衰症中出现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.