Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
Cell. 2014 Jul 17;158(2):327-338. doi: 10.1016/j.cell.2014.04.053. Epub 2014 Jul 3.
Toxic DNA-protein crosslinks (DPCs) arise by ionizing irradiation and UV light, are particularly caused by endogenously produced reactive compounds such as formaldehyde, and also occur during compromised topoisomerase action. Although nucleotide excision repair and homologous recombination contribute to cell survival upon DPCs, hardly anything is known about mechanisms that target the protein component of DPCs directly. Here, we identify the metalloprotease Wss1 as being crucial for cell survival upon exposure to formaldehyde and topoisomerase 1-dependent DNA damage. Yeast mutants lacking Wss1 accumulate DPCs and exhibit gross chromosomal rearrangements. Notably, in vitro assays indicate that substrates such as topoisomerase 1 are processed by the metalloprotease directly and in a DNA-dependent manner. Thus, our data suggest that Wss1 contributes to survival of DPC-harboring cells by acting on DPCs proteolytically. We propose that DPC proteolysis enables repair of these unique lesions via downstream canonical DNA repair pathways.
有毒的 DNA-蛋白质交联（DPC）是由电离辐射和紫外线引起的，特别是由内源性产生的反应性化合物如甲醛引起的，也会在拓扑异构酶功能受损时发生。尽管核苷酸切除修复和同源重组有助于 DPC 后细胞的存活，但对于直接针对 DPC 蛋白质成分的机制几乎一无所知。在这里，我们确定金属蛋白酶 Wss1 对于暴露于甲醛和拓扑异构酶 1 依赖性 DNA 损伤后的细胞存活至关重要。缺乏 Wss1 的酵母突变体积累 DPC 并表现出染色体大片段重排。值得注意的是，体外实验表明，金属蛋白酶直接以 DNA 依赖性的方式处理拓扑异构酶 1 等底物。因此，我们的数据表明，Wss1 通过对 DPC 进行蛋白水解作用来促进含有 DPC 的细胞的存活。我们提出 DPC 蛋白水解通过下游经典的 DNA 修复途径来修复这些独特的损伤。
