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，因此它已经进化出各种机制来消除遗传物质所遭受的破坏性改变。此外，在多细胞生物中，维持基因组完整性对于成功抑制肿瘤至关重要，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（ICLs）的化合物既是重要的抗癌剂，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尚不清楚。使用生化方法，我们已经确定了一些蛋白质需要处理体外补骨脂素ICLs。这些蛋白质包括Erccl， Xpf, Msh2，

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.