Connecting BRCA1 functions with DNA crosslink sensitivity

项目摘要 为了对抗DNA损伤的积累，真核细胞利用错综复杂的途径网络， 促进损伤识别、检查点信号和DNA修复。损害反应的组成部分 网络与各种遗传疾病有关，这些疾病的典型特征是对DNA损伤的超敏反应 毒剂和癌症易感性。特别是，肿瘤抑制基因BRCA1被描述为主控基因 基因组稳定性的调节者，因为它参与了损伤反应的各个方面。尽管 BRCA1的S确立了在乳腺癌和卵巢癌的发生发展中的作用，从分子上理解了其 功能仍然有限。我们最近发现非洲爪哇的卵提取物概括了BRCA1的功能 在人类和小鼠模型中观察到的，为未来的机械学提供了一个可溶的、高度服从的系统 学习。首先，我们将关注BRCA1的S在随后的复制解旋酶的分解中所扮演的新角色 与DNA交联物相撞。卸载CMG解旋酶复合体(由CDC45、MCM2-7和 GINS)需要接触和修复潜在的损伤，这表明解旋酶的驱逐可能是一种 DNA损伤耐受的基本机制。我们还将确定BRCA1的S是如何发挥作用的 连接到蜂窝敏感度，使我们能够设计和测试新的策略，以改进基于交叉链路的 治疗学。展望未来，我们将把分析扩展到其他BRCA1功能，以建立 全面了解BRCA1的S在DNA修复和肿瘤抑制中的许多作用。

Project Summary To counter the accumulation of DNA damage, eukaryotic cells employ an intricate network of pathways that promote damage recognition, checkpoint signaling, and DNA repair. Components of the damage response network have been linked to various genetic disorders that are typified by hypersensitivity to DNA damaging agents and cancer predisposition. In particular, the tumor suppressor BRCA1 has been described as a master regulator of genome stability due to its involvement in various aspects of the damage response. Despite BRCA1's established role in the development of breast and ovarian cancers, a molecular understanding of its functions remains limited. We recently showed that Xenopus egg extracts recapitulate BRCA1 functions observed in human and mouse models, providing a soluble, highly amenable system for future mechanistic studies. Initially, we will focus on BRCA1's newly described role in dismantling the replicative helicase after it collides with a DNA crosslink. Unloading the CMG helicase complex (comprised of Cdc45, MCM2-7, and GINS) is required to access and repair the underlying lesion, suggesting that helicase eviction may be a fundamental mechanism of DNA damage tolerance. We will also identify how BRCA1's functions are connected to cellular sensitivity, enabling us to devise and test new strategies for improved crosslink-based therapeutics. Going forward, we will extend our analysis to additional BRCA1 functions to establish a comprehensive understanding of BRCA1's many roles in DNA repair and tumor suppression.