The Role of LEM Domain Proteins in Nuclear Function

LEM 结构域蛋白在核功能中的作用

• 批准号: 10189633
• 负责人: PAMELA K. GEYER
• 金额: $ 38.53万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10189633
• 关键词: ATR checkpoint; Adult; Affect; Binding; Binding Proteins; CHEK2 gene; Cell Death; Cell Maintenance; Cells; Cessation of life; Chromatin; Chromosomes; Clustered Regularly Interspaced Short Palindromic Repeats; Complex; Cyst; Cytology; DNA; DNA Damage; Data; Defect; Deformity; Development; Disease; Disease model; Drosophila genus; Failure; Family; Fatty acid glycerol esters; Functional disorder; Gene Expression Profile; Genes; Genetic; Genome; Germ Cells; Health; Heterochromatin; High-Throughput RNA Sequencing; Homeostasis; Human; Interphase Cell; Lead; Link; Membrane; Mitosis; Monitor; Mutation; Nuclear; Nuclear Envelope; Nuclear Inner Membrane; Nuclear Lamina; Nuclear Structure; Ontology; Pathway interactions; Phenotype; Phosphotransferases; Play; Premature aging syndrome; Proteins; Role; Shapes; Signal Pathway; Signal Transduction; Skeletal Muscle; Skin; Stress; Structural defect; Structure; Tertiary Protein Structure; Testing; Tissues; Transcriptional Activation; Variant; adult stem cell; barrier-to-autointegration factor; base; bone; delta protein; ds-DNA; experimental study; germline stem cells; histone-binding proteins; improved; knock-down; mutant; novel; overexpression; prevent; response; sensor; stem cell homeostasis; stem cell population; stem cell survival; stem cells; therapeutic development; tool; transcription factor; transcriptome

ABSTRACT Human laminopathies are caused by mutations in genes encoding nuclear lamina (NL) proteins. These proteins form an extensive network that lies beneath the inner nuclear membrane. A unifying disease model suggests that lost tissue homeostasis is due to a failure to maintain adult stem cells. Although NL proteins responsible for laminopathies have been identified, it remains unclear how these proteins maintain healthy stem cell populations and promote tissue homeostasis. The conserved NL family of LEM-domain (LEM-D) proteins play a critical role in building nuclear structure and the NL. LEM-D proteins bind Barrier-to-Autointegration Factor (BAF), a conserved double stranded DNA and histone binding protein. Interactions between LEM-D proteins and BAF target nuclear membranes to chromosomes during nuclear assembly after mitosis. In addition, LEM-D proteins interact with BAF to tether the genome to the nuclear periphery and establish repressed chromatin domains in non-dividing cells. We investigate the Drosophila LEM-D family, focusing on Otefin, a LEM-D protein that is required for survival of adult germline stem cells (GSCs). The otefin mutant GSCs carry structural deformities of the NL and chromatin changes that are shared with laminopathic cells. My lab discovered that these mutant GSCs die because of activation of a novel checkpoint pathway that uses two DNA damage response (DDR) kinases, ATR and Checkpoint kinase 2 (Chk2). Although otefin mutant GSCs carry DNA damage, damage accumulation depends upon Chk2, demonstrating that DNA damage results from checkpoint activation. Based on these and other data, we hypothesize that NL deformation is responsible for activation of ATR and Chk2, a prediction supported by emerging evidence that ATR is a global sensor of structural deformities of cellular components. In this proposal, two Aims are proposed. In Aim 1, we will define the mechanism of ATR/Chk2 activation in otefin mutant GSCs. In Aim 2, we define Chk2- dependent pathways involved in GSC death. We expect our studies will have a broad impact. Nuclear shape changes are shared features of laminopathies and premature aging syndromes. We predict that activation of the NL checkpoint might contribute to lost stem cell maintenance in these diseases.

抽象的 人椎板病是由编码核层（NL）的基因突变引起的 蛋白质。这些蛋白质形成一个广泛的网络，位于内部核下方 膜。一个统一的疾病模型表明，组织稳态丧失是由于 无法维持成年干细胞。虽然NL蛋白负责椎板病 已经确定了，尚不清楚这些蛋白如何维持健康的干细胞 种群并促进组织稳态。 LEM域的保守NL家族 （LEM-D）蛋白质在建立核结构和NL中起关键作用。 LEM-D 蛋白质结合屏障到自动的组合因子（BAF），保守的双链DNA 和组蛋白结合蛋白。 LEM-D蛋白与BAF目标之间的相互作用 有丝分裂后核总成过程中核膜。此外， LEM-D蛋白与BAF相互作用，将基因组绑定到核外围，并 在非分裂细胞中建立抑制染色质结构域。我们调查 果蝇LEM-D家族，专注于Otefin，这是一种LEM-D蛋白，是必需的 成人种系干细胞（GSC）的存活。 Otefin突变体GSC携带结构 与椎板病细胞共享的NL和染色质变化的畸形。我的 实验室发现，这些突变的GSC因激活新的检查点而死亡 使用两个DNA损伤响应（DDR）激酶，ATR和检查点的途径 激酶2（CHK2）。尽管otefin突变GSC遭受DNA损伤，但损害 积累取决于CHK2，表明DNA损伤是由 检查点激活。基于这些和其他数据，我们假设NL 变形负责ATR和CHK2的激活，这是由 新兴的证据表明ATR是细胞结构畸形的全球传感器 成分。在此提案中，提出了两个目标。在AIM 1中，我们将定义 otefin突变体GSC中ATR/CHK2激活的机理。在AIM 2中，我们定义CHK2-- 涉及GSC死亡的依赖途径。我们预计我们的学习将有一个广泛的 影响。核形状变化是椎板病的共同特征和过早的特征 衰老综合征。我们预测NL检查站的激活可能会导致丢失 这些疾病中的干细胞维持。