Connecting BRCA1 functions with DNA crosslink sensitivity

项目摘要 为了对抗DNA损伤的积累，真核细胞采用了一种复杂的途径网络， 促进损伤识别、检查点信号传导和DNA修复。损害应对的组成部分 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 药物和癌症易感性。特别地，肿瘤抑制因子BRCA 1已被描述为主要的 由于其参与损伤反应的各个方面，因此是基因组稳定性的调节剂。尽管 BRCA 1在乳腺癌和卵巢癌发展中的既定作用，对其分子机制的理解， 功能仍然有限。我们最近发现爪蟾卵提取物重现了BRCA 1的功能， 在人类和小鼠模型中观察到，为未来的机制提供了一个可溶的，高度顺从的系统。 问题研究最初，我们将集中在BRCA 1的新描述的作用，在拆除复制解旋酶后， 与DNA交联碰撞卸载CMG解旋酶复合物（由Cdc 45、MCM 2 -7和MCM 2 - 7组成）， GINS）是进入和修复潜在病变所必需的，这表明解旋酶驱逐可能是一个重要的机制。 DNA损伤耐受的基本机制。我们还将确定BRCA 1的功能是如何 连接到细胞的敏感性，使我们能够设计和测试新的策略，改善基于交联 治疗学展望未来，我们将把我们的分析扩展到其他BRCA 1功能，以建立一个 全面了解BRCA 1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.