Regulation of DNA replication kinetics by BRCA2 after DNA damage

BRCA 2的生殖系突变使携带者易患乳腺癌、卵巢癌、胰腺癌和其他癌症。基因 编码一个非常大的蛋白质，在基因组完整性控制中起关键作用，通过促进同源 重组（HR）介导的DNA双链断裂（DSB）修复，DNA损伤诱导的细胞周期 此外，BRCA 2可能在DNA复制中起直接作用， 复制，因为它的突变细胞早已被称为具有所谓的抗辐射DNA合成 (RDS)表型，反映了S期内检查点的缺陷，这是一种减慢DNA的机制 DNA损伤后的复制可能是为了给DNA修复留出时间，防止损伤的复制 DNA.然而，BRCA 2在DNA复制起始或延伸中的潜在作用尚未确定。在 我们的初步研究发现，BRCA 2与一种重要的DNA复制因子MCM 10相互作用， 这种相互作用抑制了复制叉的进展，促进了复制叉的停滞，并在复制后维持了复制叉的起源。 DNA损伤。我们假设BRCA 2通过其自身的作用调节DNA损伤后的DNA复制动力学。 与MCM 10相互作用和DNA损伤后复制动力学失调，或S期内 检查点缺陷导致突变率增加，癌症发展和治疗抗性。我们提出 3、具体目标是检验假设。在目标1中，我们将定义BRCA 2在DNA中的功能机制 DNA损伤后的复制动力学。在目标2中，我们将确定BRCA 2-MCM 10相互作用在 DNA复制保真度和癌细胞对DNA损伤疗法的反应。在目标3中，我们将确定 BRCA 2-MCM 10相互作用在自发和辐射诱导的肿瘤发展中的作用。我们的调查结果和 拟议的研究将阐明BRCA 2在DNA复制中的关键机制， DNA损伤后复制动力学的调节，并定义RDS和复制的影响 动力学失调对肿瘤发展和放化疗后肿瘤复发的影响。

Germline mutations in BRCA2 predispose carriers to breast, ovarian, pancreatic, and other cancers. The gene encodes a very large protein that plays critical roles in genome integrity control by promoting homologous recombination (HR)-mediated repair of DNA double strand breaks (DSBs), DNA damage-induced cell cycle checkpoint, and stability of stalled DNA replication forks, etc. Besides, BRCA2 may play a direct role in DNA replication, as its mutant cells have long been known to have the so-called radio-resistant DNA synthesis (RDS) phenotype, which reflects a defect in the intra-S phase checkpoint, a mechanism that slows down DNA replication after DNA damage presumably to allow time for DNA repair and prevent replication of damage DNA. However, the potential role of BRCA2 in DNA replication initiation or elongation has not been defined. In our preliminary studies, we found that BRCA2 interacts with an essential DNA replication factor, MCM10, and that this interaction restrains replication fork progression, promotes fork stalling and sustains origin firing after DNA damage. We hypothesize that BRCA2 regulates DNA replication kinetics after DNA damage through its interaction with MCM10 and that a dysregulation of replication kinetics after DNA damage, or intra-S phase checkpoint defect, leads to increased mutation rate, cancer development and therapy resistance. We propose 3 specific aims to test the hypotheses. In Aim 1, we will define the mechanisms of BRCA2 function in DNA replication kinetics after DNA damage. In Aim 2, we will determine the role of the BRCA2-MCM10 interaction in DNA replication fidelity and cancer cell response to DNA damaging therapies. In Aim 3, we will determine the role of BRCA2-MCM10 interaction in spontaneous and radiation-induced tumor development. Our findings and proposed studies will elucidate key mechanisms of BRCA2 function in DNA replication, provide new insights into the regulation of replication kinetics after DNA damage, and define the impact of RDS and replication kinetics dysregulation on cancer development and tumor relapse after radiation and chemotherapy.