Processing of Interstrand Cross-Links in Mammalian Cells

细胞修复DNA损伤的能力对其生存至关重要，因此它进化出了各种机制来消除遗传物质遭受的腐蚀性改变。此外，在多细胞生物体中，保持基因组完整性是成功抑制肿瘤的关键，DNA修复基因的突变等位基因已被证明具有遗传易感性。在DNA中引入链间交联(ICL)的化合物既是重要的抗癌药物，也是可能的诱变剂和致癌物。然而，哺乳动物细胞中这些损伤的修复机制还知之甚少。使用生化方法，我们已经确定了在体外处理补骨脂素ICL所需的一些蛋白质。这些蛋白包括Ercc1、Xpf、Msh2、 Msh3、RPA、增殖细胞核抗原和涉及人类PSO4同源物的复合体。这项建议的目的是将我们的生化研究扩展到确定在体外处理补骨脂素ICL所需的其他因素，确定其他类别的ICL的体外处理是由相同还是不同的成分介导的，并通过直接监测它们在体内的去除来确定观察到的ICL体外处理的相关性。

The cell's ability to repair damage to its DNA is critical for its survival, and accordingly it has evolved a variety of mechanisms to remove the corruptive alterations to which the genetic material is subject. In addition, in multicellular organisms, maintenance of genomic integrity is critical in successful tumor suppression, and mutant alleles of DNA repair genes have been shown to confer an inherited predisposition to cancer. Compounds that introduce interstrand crosslinks (ICLs) in DNA are both important anticancer agents as well as possible mutagens and carcinogens. However, the mechanisms of repair of these lesions in mammalian cells are poorly understood. Using biochemical approaches we have identified a number of proteins that are required for processing of psoralen ICLs in vitro. These proteins include Erccl, Xpf, Msh2, Msh3, RPA, PCNA, and a complex involving the human homolog of PSO4. The goals of this proposal are to extend our biochemical studies to the identification of additional factors that are required for processing psoralen ICLs in vitro, to determine if the in vitro processing of other classes of ICLs is mediated by the same or different components, and to determine the relevance of the observed in vitro processing of ICLs by directly monitoring their removal in vivo.