FANCM in repair of stalled replication forks

复制叉停滞在异常DNA结构的位点是基因组不稳定性的公认原因。 增加的复制叉停滞（“复制应激”）是癌细胞的共同特征，这表明， 停滞叉的缺陷加工是癌症中基因组不稳定性的常见机制。范可尼 贫血（FA）通路在停滞复制叉的代谢和修复中起重要作用。FA是一种罕见的， 由FA基因失活引起的常染色体隐性遗传病。临床 FA的临床表现包括儿童贫血和进行性骨髓衰竭，以及短 影响多种器官的身高和先天性缺陷。患癌症的风险，包括实体瘤，是 升高，尤其是急性髓细胞性白血病的发病率高。基因编码的早期 FA通路的应答者FANCM在某些乳腺癌中存在突变。FA途径重叠 在功能上与遗传性乳腺癌/卵巢癌易感性的BRCA途径--一个关键的调节因子， 同源重组FA通路也被复制应激激活，表明FA通路在复制应激中的一般作用。 FA基因在人类癌症和许多其他疾病中的作用。因此，破译的行动机制， FA通路对人类健康具有广泛的意义。我们最近将大肠杆菌Tus/Ter 用于哺乳动物细胞的复制叉阻滞复合物，并已将其用于定量无误差和 由哺乳动物染色体复制叉阻断诱导的易错同源重组。更 最近，我们在哺乳动物细胞中发现了一种新的复制叉停滞的异常修复产物， 小的（<10 kb）微同源介导的串联重复在复制停滞位点形成。FANCM 在抑制失速分叉处的异常修复产物方面起着至关重要的作用。在这里提出的工作中，我们 将使用Scully实验室最近开发的新工具来分析FANCM如何调节同源 在停滞的复制叉处进行重组。我们将查明刚果国民军镇压 在停滞的分叉处进行串联复制。这项工作的成功将导致确定新的治疗靶点 在癌症和其他人类疾病中。

Replication fork stalling at sites of abnormal DNA structure is a recognized cause of genomic instability. Increased replication fork stalling (“replication stress”) is a common feature of cancer cells, suggesting that defective processing of the stalled fork is a common mechanism of genomic instability in cancer. The Fanconi Anemia (FA) pathway has a major role in the metabolism and repair of stalled replication forks. FA is a rare, autosomal recessive (or X-linked) disease caused by inactivation of any one of several FA genes. The clinical manifestations of FA include childhood anemia and progressive bone marrow failure, together with short stature and congenital defects affecting a wide variety of organs. The risk of cancer, including solid tumors, is elevated, with particularly high incidence of acute myelogenous leukemia. The gene encoding an early responder of FA pathway, FANCM, is found mutated in some breast cancers. The FA pathway overlaps functionally with the BRCA pathway of hereditary breast/ovarian cancer predisposition—a critical regulator of homologous recombination. The FA pathway is also activated by replication stress, indicating a general role for the FA genes in human cancer and in many other diseases. Thus, deciphering the mechanisms of action of the FA pathway has broad significance for human health. We recently adapted the Escherichia coli Tus/Ter replication fork arrest complex for use in mammalian cells and have used it to quantify both error-free and error-prone homologous recombination induced by a mammalian chromosomal replication fork block. More recently, we identified a novel aberrant repair product of replication fork arrest in mammalian cells, in which small (<10 kb) microhomology-mediated tandem duplications form at the site of replication arrest. FANCM plays a crucial role in suppressing these aberrant repair products at stalled forks. In work proposed here, we will use novel tools, recently developed by the Scully lab, to analyze how FANCM regulates homologous recombination at stalled replication forks. We will identify the mechanisms by which FANCM suppresses tandem duplication at stalled forks. Success in this work will lead to the identification of new targets for therapy in cancer and other human diseases.