Regulation of Ionizing Radiation Induced DNA Damage Response

电离辐射诱导的 DNA 损伤反应的调节

• 批准号: 8444597
• 负责人: Xiaochun Yu
• 金额: $ 28.12万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8444597
• 关键词: BRCA1 gene; Binding; Cancer-Predisposing Gene; Cell Cycle Progression; Cells; Chromatin; DNA; DNA Damage; DNA Repair; DNA damage checkpoint; Data; FHA Domain; Functional disorder; Genome Stability; Genomics; Growth; Histone H4; Histones; Incidence; Ionizing radiation; Knockout Mice; Maintenance; Methylation; Molecular; Monitor; Mono-S; Mus; Pathway interactions; Phenotype; Phosphotransferases; Play; Prevention; Proteins; Radiation Induced DNA Damage; Regulation; Ring Finger Domain; Risk; Role; Scaffolding Protein; Signal Transduction; Site; Sterility; Time; Tumor Suppression; Tumor Suppressor Proteins; Ubiquitination; base; cancer cell; hazard; human 53BP1 protein; human H2AX protein; in vivo; insight; male; malignant breast neoplasm; public health relevance; research study; response; tumor; tumorigenesis; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Ionizing radiation induces DNA double stand breaks, which activates a signal cascade initiated by ATM/ATR kinases. The damage signals stop the cell cycle progression and allow enough time for DNA damage repair. Here, we have identified an important regulator, RNF8 (Ring Finger protein 8) that participates in the activation of DNA damage response. Following DNA damage, the FHA domain of RNF8 recognizes phosphorylated MDC1, a binding partner of histone H2AX in DNA damage response, which targets RNF8 to DNA damage sites. Histone H2AX is a scaffold protein that retains DNA damage response proteins at the DNA damage sites. Since RNF8 is an E3 ubiquitin ligase, we have found that RNF8 controls histone H2AX ubiquitination following DNA damage. RNF8-dependent H2AX ubiquitination may regulate downstream 53BP1 (p53 Binding Protein 1) and BRCA1 (Breast Cancer Susceptibility Gene 1) translocation to DNA damage sites. Both BRCA1 and 53BP1 are not only downstream targets of ATM/ATR kinases, but also important tumor suppressors. Moreover, we have generated RNF8 knock-out mice. The RNF8 null mice are viable. But male RNF8 -/- mice are sterile. RNF8 -/- mice are hypersensitive to ionizing radiation. These phenotypes are very similar to those of histone H2AX and MDC1 knock-out mice. Thus, based on our preliminary studies, we hypothesize that RNF8 plays a major role in activation of DNA damage response and participates in tumor prevention. We propose following experiments to examine our hypotheses. Aim1: To investigate the role of RNF8-dependent histone ubiquitination in DNA damage response. Aim2: To study the role of RNF8 in histone methylation in response to DNA damage. Aim3: To examine the role of RNF8 in tumor suppression. In summary, our proposed studies will not only provide insights into the mechanisms of the activation of DNA damage response, but also contribute to our understanding of the maintenance of genomic integrity and tumor prevention.

描述（由申请人提供）： 电离辐射诱导DNA双支架断裂，这激活了由ATM/ATR激酶引发的信号级联。损伤信号阻止了细胞周期的进展，并为DNA损伤修复提供了足够的时间。在这里，我们已经确定了一个重要的调节剂RNF8（环手指蛋白8），该调节剂参与DNA损伤反应的激活。 DNA损伤后，RNF8的FHA结构域识别DNA损伤响应中组蛋白H2AX的磷酸化MDC1磷酸化的MDC1，该损伤响应中靶向RNF8靶向DNA损伤位点。组蛋白H2AX是一种支架蛋白，可在DNA损伤位点保留DNA损伤反应蛋白。由于RNF8是E3泛素连接酶，因此我们发现RNF8在DNA损伤后控制组蛋白H2AX泛素化。依赖RNF8的H2AX泛素化可能会调节下游53BP1（p53结合蛋白1）和BRCA1（乳腺癌易感性基因1）转移到DNA损伤位点。 BRCA1和53BP1不仅是ATM/ATR激酶的下游靶标，而且是重要的肿瘤抑制剂。此外，我们已经产生了RNF8敲除小鼠。 RNF8空小鼠可行。但是雄性RNF8 - / - 小鼠是无菌的。 RNF8 - / - 小鼠对电离辐射非常敏感。这些表型与组蛋白H2AX和MDC1敲除小鼠非常相似。因此，根据我们的初步研究，我们假设RNF8在激活DNA损伤反应并参与预防肿瘤中起着重要作用。我们建议以下实验检查我们的假设。 AIM1：研究RNF8依赖性组蛋白泛素化在DNA损伤反应中的作用。 AIM2：研究RNF8在响应DNA损伤的组蛋白甲基化中的作用。 AIM3：检查RNF8在肿瘤抑制中的作用。总而言之，我们提出的研究不仅将提供有关DNA损伤反应激活机制的见解，而且还有助于我们理解维持基因组完整性和预防肿瘤。