Chromatin's Role in Repair of Radiation-induced Damage.

染色质在修复辐射引起的损伤中的作用。

• 批准号: 7210170
• 负责人: Jessica K Tyler
• 金额: $ 26.86万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7210170
• 关键词: DNA damage; DNA repair; DNA replication; chromatin; chromosome aberrations; developmental genetics; endonuclease; enzyme induction /repression; eukaryote; fungal genetics; gene expression; gene targeting; genetic manipulation; genetic mapping; genetic models; histones; protein biosynthesis; protein structure function; radiation genetics; radiation sensitivity; yeasts

DESCRIPTION (provided by applicant): The goal of this research is to define the fundamental role that chromatin plays during the repair of radiation-induced double-strand breaks (DSBs). Cell survival and maintenance of genome integrity are critically dependent on the repair of DSBs. If repaired incorrectly, DSBs result in aberrations such as chromosomal rearrangements and can lead to formation of cancers. In order to fully understand the repair of radiation-induced DSBs, it is important to consider the natural context - chromatin. The packaging of the genome into chromatin is likely to influence DNA repair processes by analogy to the situation with gene expression. Accordingly, we have discovered that the chromatin assembly factors Asf1 and CAF-1 are essential for cell survival following the repair of radiation-induced, endogenous and developmentally-programmed DNA damage in vivo. Furthermore, we have recently shown for the first time that histone acetylation changes locally during DSB repair via the homologous recombination pathway, and that cells die if they cannot change their acetylation state during DSB repair. We will test the hypothesis that specific post- translational modifications of histones, remodeling, disassembly, and reassembly of the chromatin occur at the DSB during repair. Furthermore, we will define the molecular mechanism as to why these chromatin dynamics are essential and intrinsic to chromosomal repair. Finally, we will identify novel chromatin modifications that are critical for DSB repair. In order to gain insight into the repair of radiation-induced DNA damage, the approach will be to synchronously induce a highly specific endonuclease within yeast to study the molecular events at a unique defined DSB. Using this model system, we will map the changes to the chromatin structure that precede, accompany and follow the repair of a DSB. The findings of the proposed experiments will provide the foundation for understanding the fundamental, yet poorly understood, role of chromatin structure during the repair of radiation-induced DSBs. As such, these studies are directly applicable to human diseases that result from radiation-induced loss of genome integrity, including many forms of cancer.

描述（由申请人提供）：本研究的目标是确定染色质在修复辐射引起的双链断裂 (DSB) 过程中所发挥的基本作用。细胞的存活和基因组完整性的维持严重依赖于 DSB 的修复。如果修复不正确，DSB 会导致染色体重排等畸变，并可能导致癌症的形成。为了充分了解辐射诱导的 DSB 修复，重要的是要考虑自然环境 - 染色质。与基因表达的情况类似，基因组包装到染色质中可能会影响 DNA 修复过程。因此，我们发现染色质组装因子 Asf1 和 CAF-1 对于体内辐射诱导的内源性和发育程序性 DNA 损伤修复后的细胞存活至关重要。此外，我们最近首次表明组蛋白乙酰化在 DSB 修复过程中通过同源重组途径发生局部变化，并且如果细胞在 DSB 修复过程中不能改变其乙酰化状态，则会死亡。我们将检验以下假设：修复过程中 DSB 发生组蛋白的特定翻译后修饰、染色质的重塑、拆卸和重新组装。此外，我们将定义分子机制，解释为什么这些染色质动力学对于染色体修复至关重要和固有。最后，我们将鉴定对 DSB 修复至关重要的新染色质修饰。为了深入了解辐射引起的 DNA 损伤的修复，该方法将在酵母内同步诱导高度特异性的核酸内切酶，以研究独特定义的 DSB 的分子事件。使用这个模型系统，我们将绘制 DSB 修复之前、伴随和之后染色质结构的变化。拟议实验的结果将为理解染色质结构在辐射诱导的 DSB 修复过程中的基本作用（但目前人们对此知之甚少）提供基础。因此，这些研究可直接适用于由辐射引起的基因组完整性丧失而导致的人类疾病，包括许多形式的癌症。