Regulation of DNA replication kinetics by BRCA2 after DNA damage

BRCA2 种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 编码一种非常大的蛋白质，通过促进同源性在基因组完整性控制中发挥关键作用 重组 (HR) 介导的 DNA 双链断裂 (DSB) 修复、DNA 损伤诱导的细胞周期 检查点、停滞的DNA复制叉的稳定性等。此外，BRCA2可能在DNA中发挥直接作用 复制，因为人们早就知道其突变细胞具有所谓的抗辐射 DNA 合成能力 (RDS) 表型，反映了 S 相内检查点的缺陷，这是一种减慢 DNA 速度的机制 DNA 损伤后的复制可能是为了给 DNA 修复留出时间并防止损伤复制 脱氧核糖核酸。然而，BRCA2 在 DNA 复制起始或延伸中的潜在作用尚未明确。在 我们的初步研究发现，BRCA2 与重要的 DNA 复制因子 MCM10 相互作用，并且 这种相互作用抑制了复制叉的进展，促进复制叉停滞并维持复制叉后的起源激发 DNA损伤。我们假设 BRCA2 通过其在 DNA 损伤后调节 DNA 复制动力学 与 MCM10 的相互作用以及 DNA 损伤或 S 内阶段后复制动力学的失调 检查点缺陷会导致突变率、癌症发展和治疗耐药性增加。我们建议 3.具体目的是检验假设。在目标 1 中，我们将定义 DNA 中 BRCA2 功能的机制 DNA损伤后的复制动力学。在目标 2 中，我们将确定 BRCA2-MCM10 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 BRCA2-MCM10 相互作用在自发和辐射诱导的肿瘤发展中的作用。我们的发现和 拟议的研究将阐明 BRCA2 在 DNA 复制中功能的关键机制，提供新的见解 研究 DNA 损伤后复制动力学的调节，并定义 RDS 和复制的影响 放疗和化疗后癌症发展和肿瘤复发的动力学失调。

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.