Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm SE-171 77, Sweden.
Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.
Genetics. 2020 Dec;216(4):1009-1022. doi: 10.1534/genetics.120.303494. Epub 2020 Oct 8.
Double-strand breaks that are induced postreplication trigger establishment of damage-induced cohesion in , locally at the break site and genome-wide on undamaged chromosomes. The translesion synthesis polymerase, polymerase η, is required for generation of damage-induced cohesion genome-wide. However, its precise role and regulation in this process is unclear. Here, we investigated the possibility that the cyclin-dependent kinase Cdc28 and the acetyltransferase Eco1 modulate polymerase η activity. Through phosphorylation and structure modeling, we showed that polymerase η is an attractive substrate for Cdc28 Mutation of the putative Cdc28-phosphorylation site Ser14 to Ala not only affected polymerase η protein level, but also prevented generation of damage-induced cohesion We also demonstrated that Eco1 acetylated polymerase η Certain nonacetylatable polymerase η mutants showed reduced protein level, deficient nuclear accumulation, and increased ultraviolet irradiation sensitivity. In addition, we found that both Eco1 and subunits of the cohesin network are required for cell survival after ultraviolet irradiation. Our findings support functionally important Cdc28-mediated phosphorylation, as well as post-translational modifications of multiple lysine residues that modulate polymerase η activity, and provide new insights into understanding the regulation of polymerase η for damage-induced cohesion.
复制后诱导的双链断裂会触发局部断裂部位和未损伤染色体上的全基因组损伤诱导的黏合的建立。跨损伤合成聚合酶聚合酶η对于全基因组损伤诱导的黏合的产生是必需的。然而，其在这个过程中的精确作用和调控尚不清楚。在这里，我们研究了细胞周期蛋白依赖性激酶 Cdc28 和乙酰转移酶 Eco1 是否调节聚合酶 η 活性的可能性。通过磷酸化和结构建模，我们表明聚合酶 η 是 Cdc28 的一个有吸引力的底物。将假定的 Cdc28 磷酸化位点丝氨酸 14 突变为丙氨酸不仅影响聚合酶 η 蛋白水平，而且阻止了损伤诱导的黏合的产生。我们还证明 Eco1 乙酰化了聚合酶 η。某些不可乙酰化的聚合酶 η 突变体显示出蛋白水平降低、核积累缺陷和对紫外线照射的敏感性增加。此外，我们发现 Eco1 和黏合蛋白网络的亚基都需要在紫外线照射后用于细胞存活。我们的研究结果支持了具有重要功能的 Cdc28 介导的磷酸化，以及调节聚合酶 η 活性的多个赖氨酸残基的翻译后修饰，为理解聚合酶 η 在损伤诱导的黏合中的调控提供了新的见解。
