Naturally occurring or drug-induced DNA-protein crosslinks (DPCs) interfere with key DNA transactions if not repaired in a timely manner. The unique family of DPC-specific proteases Wss1/SPRTN targets DPC protein moieties for degradation, including stabilized topoisomerase-1 cleavage complexes (Top1ccs). Here, we describe that the efficient DPC disassembly requires Ddi1, another conserved predicted protease in Saccharomyces cerevisiae. We found Ddi1 in a genetic screen of the tdp1 wss1 mutant defective in Top1cc processing. Ddi1 is recruited to a persistent Top1cc-like DPC lesion in an S phase-dependent manner to assist in the eviction of crosslinked protein from DNA. Loss of Ddi1 or its putative protease activity hypersensitizes cells to DPC trapping agents independently from Wss1 and 26S proteasome, implying its broader role in DPC repair. Among the potential Ddi1 targets, we found the core component of Pol II and show that its genotoxin-induced degradation is impaired in ddi1. We propose that the Ddi1 protease contributes to DPC proteolysis.

中文翻译：

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天冬氨酸蛋白酶Ddi1有助于酵母中DNA蛋白质交联修复。

如果不及时修复，自然发生的或药物诱导的DNA-蛋白质交联（DPC）会干扰关键的DNA交易。DPC特异性蛋白酶Wss1 / SPRTN的独特家族靶向DPC蛋白质部分进行降解，包括稳定的拓扑异构酶1裂解复合物（Top1ccs）。在这里，我们描述了有效的DPC拆卸需要Ddi1，酿酒酵母中的另一个保守的预测的蛋白酶。我们在Top1cc处理中的tdp1 wss1突变体的遗传筛选中发现了Ddi1。Ddi1以S期依赖的方式募集到持久性Top1cc样DPC病变中，以协助从DNA中清除交联蛋白。Ddi1或其假定的蛋白酶活性的丧失使细胞对DPC捕获剂的过敏性独立于Wss1和26S蛋白酶体，暗示其在DPC修复中的作用更广泛。在潜在的Ddi1靶标中，我们发现了Pol II的核心成分，并显示了它的基因毒素诱导的降解在ddi1中受损。我们建议Ddi1蛋白酶有助于DPC蛋白水解。