Drosophila as a model for Emery-Dreifuss muscular dystrophy

描述（由申请人提供）：核纤层蛋白形成内衬核内膜的网状结构，为细胞核提供结构支持，并通过与染色质的接触组织基因组。核纤层蛋白参与多种核过程，如基因表达的调节、DNA复制/修复和信号转导。在人类中，编码A型核纤层蛋白的LMNA基因的突变导致一系列被称为核纤层蛋白病的疾病，包括常染色体显性埃默里-德赖富斯肌营养不良症（AD-EDMD）和扩张型心肌病。尽管核纤层蛋白在几乎所有细胞中表达，但缺陷发生在特定组织中。例如，肌肉组织对A型核纤层蛋白的突变形式特别敏感。我们开发了一个强大的果蝇模型，用于研究A型核纤层蛋白的功能。果蝇A型核纤层蛋白的突变形式类似于在人类中引起疾病的那些，已经在转基因果蝇中表达。当这些突变形式在幼虫肌肉中表达时，出现导致半致死性的肌肉缺陷。成年的“逃跑者”有腿缺陷，与幼虫肌肉功能的丧失一致。在具体目标1中，我们将进行全生物体药物筛选，以鉴定拯救与肌肉中表达核纤层蛋白突变形式相关的突变表型和/或致死性的化合物。这个屏幕将与罗斯·凯根合作进行（Mt.西奈医学院），果蝇药物筛选专家。在具体目标2中，我们将测试A型核纤层蛋白变体的功能，这些变体已由凯瑟琳马修斯、史蒂文摩尔和彼得纳吉博士（爱荷华州大学）在患者中鉴定。我们将通过在果蝇肌肉中表达这些变体并测定分子缺陷和肌肉功能丧失来功能性测试这些变体。总的来说，我们的研究将临床研究与基础核纤层蛋白研究联系起来，并有可能确定用于治疗AD-EDMD的新化合物。 公共卫生相关性：Emery-Dreifuss肌营养不良症（EDMD）是一种罕见的肌营养不良症，可导致进行性肌肉萎缩和心力衰竭，估计发生率为1-2/100，000。EDMD是十二种被归类为“核纤层蛋白病”的疾病之一，其由编码核纤层蛋白的基因突变引起，核纤层蛋白是核膜的组分。我们已经组建了一个由基础研究人员和临床医生组成的团队，他们的共同目标是确定EDMD的治疗方法。为了达到这个目标，我们将使用果蝇模型的EDMD。这种无脊椎动物模型允许进行全生物体药物筛选。我们的研究将提供核纤层蛋白的功能测试，并确定可能用于EDMD治疗的化合物。

DESCRIPTION (provided by applicant): Lamins form a meshwork that lines the inner nuclear envelope, providing structural support for the nucleus and organizing the genome through contacts made with chromatin. Lamins participate in diverse nuclear processes such as the regulation of gene expression, DNA replication/repair and signal transduction. In humans, mutations in the LMNA gene, encoding the A-type lamins, cause a collection of diseases known as laminopathies, including autosomal dominant Emery-Dreifuss muscular dystrophy (AD-EDMD) and dilated cardiomyopathy. Though lamins are expressed in nearly all cells, defects occur in specific tissues. For example, muscle tissue is especially sensitive to mutant forms of A-type lamin. We developed a powerful Drosophila model for studying the function of A-type lamins. Mutant forms of the Drosophila A-type lamin analogous to those that cause disease in humans have been expressed in transgenic flies. When these mutant forms are expressed in larval muscle, muscle defects arise that result in semi-lethality. Adult "escapers" possess leg defects consistent with a loss of larval muscle function. In Specific Aim 1 we will perform a whole organism drug screen to identify compounds that rescue the mutant phenotypes and/or lethality associated with expressing mutant forms of lamin in muscle. This screen will be carried out in collaboration with Ross Cagan (Mt. Sinai School of Medicine), an expert in Drosophila drug screens. In Specific Aim 2 we will test the function of A-type lamin variants that have been identified in patients by Drs. Katherine Matthews, Steven Moore and Peter Nagy (University of Iowa). We will functionally test these variants by expressing them in Drosophila muscle and assaying for molecular defects and loss of muscle function. Collectively, our studies link clinical investigations with basic lamin research and have the potential to identify new compounds for the treatment of AD-EDMD. PUBLIC HEALTH RELEVANCE: Emery-Dreifuss muscular dystrophy (EDMD), a rare form of muscular dystrophy that causes progressive muscle wasting and cardiac failure, is estimated to occur in 1-2/100,000 individuals. EDMD is one of twelve diseases classified as "laminopathies", which are caused by mutations in the gene encoding lamin, a component of the nuclear envelope. We have assembled a team of basic researchers and clinicians that share the goal of identifying a therapy for EDMD. To reach this goal we will use a fruit fly model of EDMD. This invertebrate model allows for whole organism drug screens. Our studies will provide functional tests for lamins and identify compounds for possible therapeutic treatment of EDMD.