CHROMATIN REPLICATION AND HEAT-INDUCED CELL DEATH

染色质复制和热诱导的细胞死亡

• 批准号: 3167109
• 负责人: RAYMOND L WARTERS
• 金额: $ 17.35万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-08-01 至 1993-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3167109
• 关键词: DNA topoisomerases; HeLa cells; X ray; ataxia telangiectasia; cell death; chromatin; chromosome disorders; cytoplasm; cytotoxicity; disease /disorder model; hamsters; histones; ionizing radiation; macromolecule; mutant; neoplasm /cancer radiation therapy; neoplasm /cancer thermotherapy; radiation genetics; radiation sensitivity; radioimmunoassay; tissue /cell culture

The overall objective of this proposal is to determine the combined effect(s) of hyperthermia (40 to 48 degree) and radiation (0 to 100 Gy) exposure on DNA replication in mammalian cells, and the role of lesions in DNA replication in heat-, or combined heat and radiation-induced S phase cell cytotoxicity. The capacity of heated and/or irradiated S phase cells: to redistribute DNA being polymerized at the nuclear matrix into bulk DNA, to process this nascent DNA into higher- order (solenoid) chromatin structure, and ultimately to ligate this DNA fully into chromosome-sized DNA will be determined. The model we will test in heated cells is that long-term damage to the nuclear matrix, or its associated structures or macromolecules, results in residual lesions in DNA being replicated during hyperthermic exposure. A similar model will be tested to determine whether S phase cell sensitivity in the radiation sensitive ataxia telangiectasia human cells, the xrs CHO double strand break repair mutants or "wild-type" cells exposed caffeine during X irradiation results from the failure of these cells to ligate replicating DNA fully into chromosomes. The nuclear alterations being examined in heated cells are the thermal denaturation of nuclear matrix protein(s), the precipitation of nuclear protein and RNA onto the nuclear matrix and the potentially irreversible association of the topoisomerase enzymes onto DNA adjacent to the nuclear matrix. We will determine whether these lesions in the DNA replicative process in heated cells result in the long-term presence of DNA strand breaks in DNA replicated during cell heating and thus ultimately to chromosome aberration formation and cytotoxicity.

该提案的总体目标是确定 高温（40 至 48 度）和的综合效应 辐射（0 至 100 Gy）暴露对 DNA 复制的影响 哺乳动物细胞，以及损伤在 DNA 复制中的作用 热或热和辐射联合诱导的 S 期细胞 细胞毒性。 加热和/或辐照S相的能力 细胞：重新分配在核聚合的DNA 基质转化为大量 DNA，将新生 DNA 加工成更高级的 顺序（螺线管）染色质结构，并最终连接此 DNA完全转化为染色体大小的DNA将被测定。 这 我们将在加热电池中测试的模型是，长期损坏 核基质或其相关结构或大分子， 导致 DNA 复制过程中残留损伤 高温暴露。 将测试类似模型 判断S期细胞是否对放射线敏感 敏感共济失调毛细血管扩张人类细胞，xrs CHO 双 链断裂修复突变体或“野生型”细胞暴露于咖啡因 在X射线照射期间，这些细胞未能 将复制的 DNA 完全连接到染色体中。 核 在加热的电池中检查的变化是热 核基质蛋白的变性，沉淀 核蛋白和 RNA 沉积到核基质上 拓扑异构酶的潜在不可逆关联 到邻近核基质的 DNA 上。 我们将确定 这些损伤是否在DNA复制过程中受热 细胞中DNA链断裂的长期存在 DNA 在细胞加热过程中复制，最终 染色体畸变的形成和细胞毒性。