Lozada Enerlyn, Yi Jingjie, Luo Jianyuan, Orren David K
Graduate Center for Toxicology, University of Kentucky College of Medicine, 356 HSRB, 1095 V.A. Drive, Lexington, KY, 40536, USA.
Biogerontology. 2014 Aug;15(4):347-66. doi: 10.1007/s10522-014-9506-3. Epub 2014 Jun 26.
Loss of Werner syndrome protein function causes Werner syndrome, characterized by increased genomic instability, elevated cancer susceptibility and premature aging. Although WRN is subject to acetylation, phosphorylation and sumoylation, the impact of these modifications on WRN's DNA metabolic function remains unclear. Here, we examined in further depth the relationship between WRN acetylation and its role in DNA metabolism, particularly in response to induced DNA damage. Our results demonstrate that endogenous WRN is acetylated somewhat under unperturbed conditions. However, levels of acetylated WRN significantly increase after treatment with certain DNA damaging agents or the replication inhibitor HU. Use of DNA repair-deficient cells or repair pathway inhibitors further increase levels of acetylated WRN, indicating that induced DNA lesions and their persistence are at least partly responsible for increased acetylation. Notably, acetylation of WRN correlates with inhibition of DNA synthesis, suggesting that replication blockage might underlie this effect. Moreover, WRN acetylation modulates its affinity for and activity on certain DNA structures, in a manner that may enhance its relative specificity for physiological substrates. Our results also show that acetylation and deacetylation of endogenous WRN is a dynamic process, with sirtuins and other histone deacetylases contributing to WRN deacetylation. These findings advance our understanding of the dynamics of WRN acetylation under unperturbed conditions and following DNA damage induction, linking this modification not only to DNA damage persistence but also potentially to replication stalling caused by specific DNA lesions. Our results are consistent with proposed metabolic roles for WRN and genomic instability phenotypes associated with WRN deficiency.
沃纳综合征蛋白功能丧失会导致沃纳综合征，其特征为基因组不稳定性增加、癌症易感性升高和早衰。尽管WRN会发生乙酰化、磷酸化和SUMO化修饰，但这些修饰对WRN的DNA代谢功能的影响仍不清楚。在此，我们更深入地研究了WRN乙酰化与其在DNA代谢中的作用之间的关系，特别是在应对诱导性DNA损伤时的关系。我们的结果表明，内源性WRN在未受干扰的条件下会有一定程度的乙酰化。然而，在用某些DNA损伤剂或复制抑制剂HU处理后，乙酰化WRN的水平会显著增加。使用DNA修复缺陷细胞或修复途径抑制剂会进一步提高乙酰化WRN的水平，这表明诱导性DNA损伤及其持续性至少部分是乙酰化增加的原因。值得注意的是，WRN的乙酰化与DNA合成的抑制相关，这表明复制受阻可能是这种效应的基础。此外，WRN乙酰化以一种可能增强其对生理底物相对特异性的方式调节其对某些DNA结构的亲和力和活性。我们还表明，内源性WRN的乙酰化和去乙酰化是一个动态过程，沉默调节蛋白和其他组蛋白脱乙酰酶参与了WRN的去乙酰化。这些发现加深了我们对未受干扰条件下以及DNA损伤诱导后WRN乙酰化动态变化的理解，不仅将这种修饰与DNA损伤的持续性联系起来，还可能与特定DNA损伤导致的复制停滞联系起来。我们的结果与WRN的拟代谢作用以及与WRN缺乏相关的基因组不稳定性表型一致。
