Regulation of DNA replication kinetics by BRCA2 after DNA damage

BRCA2的种系突变使携带者更容易患上乳腺癌、卵巢癌、胰腺癌和其他癌症。基因 编码一种非常大的蛋白质，通过促进同源基因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，以及停滞的DNA复制叉子的稳定性等。此外，BRCA2可能在DNA中发挥直接作用 复制，因为它的突变细胞早就知道有所谓的抗辐射DNA合成 (Rds)表型，反映了S内阶段检查点的缺陷，这是一种减缓dna的机制 DNA损伤后的复制可能是为了有时间进行DNA修复和防止损伤的复制 DNA然而，BRCA2在DNA复制起始或延伸中的潜在作用尚未确定。在……里面 我们的初步研究发现，BRCA2与一种重要的DNA复制因子MCM10相互作用，并且 这种相互作用抑制了复制分叉的进展，促进了分叉失速，并在 DNA损伤。我们假设BRCA2通过其受体调节DNA损伤后的DNA复制动力学 与MCM10的相互作用以及DNA损伤后复制动力学的失调，或S期内 检查点缺陷，导致突变率增加，癌症发展和治疗耐药性增加。我们建议 3个具体目的是对假设进行检验。在目标1中，我们将定义BRCA2在DNA中的作用机制 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复制的保真度和癌细胞对DNA损伤治疗的反应。在目标3中，我们将确定 BRCA2-MCM10相互作用在自发和辐射诱导肿瘤发生中的作用。我们的调查结果和 拟议的研究将阐明BRCA2在DNA复制中的关键机制，提供新的见解 DNA损伤后复制动力学的调节，并定义RDS和复制的影响 放化疗后肿瘤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.