Chromatin Degradation During Apoptosis

细胞凋亡过程中染色质降解

• 批准号: 8626408
• 负责人: DING XUE
• 金额: $ 27.84万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8626408
• 关键词: Alzheimer' s Disease; Animal Model; Animals; Apoptosis; Apoptotic; Autoimmune Diseases; Biochemical; Biological; Biological Assay; Biological Process; Caenorhabditis elegans; Calcium; Cancer Etiology; Caspase; Cell Death; Cell Death Signaling Process; Cell Nucleus; Cell physiology; Cells; Chromatin; Chromosomes; Cleaved cell; Complex; DNA; DNA Binding; DNA Double Strand Break; DNA-Binding Proteins; Defect; Deoxyribonucleases; Development; Enzymes; Event; Genes; Genetic; Homeostasis; Homologous Gene; Human; Hydroxyl Radical; Malignant Neoplasms; Mediating; Mitochondria; Molecular; Molecular Cloning; Molecular Genetics; Mutation; Pathway interactions; Peptide Hydrolases; Phosphatidylserines; Process; Pump; RNA Binding; RNA Interference; Regulation; Ribonucleases; Role; Signal Pathway; Signal Transduction; Small RNA; Specificity; Structure; Tissues; Work; base; caspase-3; cell killing; cell suicide; controlled release; forward genetics; genome wide association study; human DICER1 protein; human disease; in vitro Assay; in vivo; insight; interest; mutant; new therapeutic target; novel; nuclease; presenilin; prevent; ubiquilin

DESCRIPTION (provided by applicant): Fragmentation of chromosomal DNA is a critical step in apoptosis that prevents a cell from transcribing and replicating its genes and thus facilitates the cell killing process. Defects in this process can cause various pathological conditions, including autoimmune disorders and cancer. We have identified ten apoptotic nucleases and several non-nuclease factors involved in regulating and executing apoptotic chromosome fragmentation in C. elegans. They act in a sequential and CED-3 caspase-dependent manner to promote stepwise fragmentation and degradation of chromosomes. The process is initiated by a novel CED-3-mediated conversion of the dicer ribonuclease (RNase) into a deoxyribonuclease (DNase), which makes the first cuts on chromosomes. In parallel, a mitochondrial nuclease CPS-6 and its activator WAH-1 are released from mitochondria and translocated to the nucleus, where they interact and cooperate with other cell death nucleases to turn the initial cuts by dicer into double-strand DNA breaks, leading to fragmentation and degradation of chromosomes. In this proposed work, we will carry out molecular genetic, biochemical, cell biological, and structural analyses to understand these two critical events of apoptotic DNA degradation. In Aim 1, we will investigate the molecular and structural basis underlying CED-3-mediated conversion of the dicer RNase into a DNase. In Aim 2, we will dissect the new signaling pathway that controls cytosolic calcium increase and release of the mitochondrial apoptogeneic factors during apoptosis. In Aim 3, we will perform molecular genetic and functional characterization of two new genes, cps-13 and cps-14, that regulate and coordinate two key cell death execution events, chromosome fragmentation and phosphatidylserine (PS) externalization. These studies should reveal the novel mechanism that controls the specificity and function switch of the dicer nuclease and new signaling mechanisms and players that control the release of the mitochondrial apoptogenic factors.

描述（由申请人提供）：染色体DNA片段化是细胞凋亡的关键步骤，可阻止细胞转录和复制其基因，从而促进细胞杀伤过程。这个过程中的缺陷会导致各种病理条件，包括自身免疫性疾病和癌症。我们已经鉴定了10种凋亡核酸酶和几种非核酸酶因子参与调控和执行C.优美的它们以顺序和CED-3半胱天冬酶依赖性方式起作用，以促进染色体的逐步断裂和降解。这一过程是由一种新的CED-3介导的将dicer核糖核酸酶（RNase）转化为脱氧核糖核酸酶（DNase）启动的，该酶在染色体上进行第一次切割。与此同时，线粒体核酸酶CPS-6及其激活剂WAH-1从线粒体释放并易位到细胞核，在那里它们与其他细胞死亡核酸酶相互作用并合作，以将切割酶的初始切割转化为切割酶。 双链DNA断裂，导致染色体断裂和降解。在这项拟议的工作中，我们将进行分子遗传学，生物化学，细胞生物学和结构分析，以了解这两个关键事件的凋亡DNA降解。在目标1中，我们将研究CED-3介导的dicer RNA酶转化为DNA酶的分子和结构基础。在目标2中，我们将剖析新的信号通路，控制细胞内钙离子的增加和释放的线粒体凋亡因子在细胞凋亡。在目标3中，我们将对两个新基因cps-13和cps-14进行分子遗传学和功能表征，这两个基因调节和协调两个关键的细胞死亡执行事件，染色体片段化和磷脂酰丝氨酸（PS）外化。这些研究将揭示控制dicer核酸酶特异性和功能转换的新机制以及控制线粒体促凋亡因子释放的新信号机制和参与者。