Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA.
Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA; Interdepartmental Program in Computational Biology and Bioinformatics, Yale University, 300 George Street, Suite 501, New Haven, CT 06511, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA.
Cell Rep. 2019 Aug 20;28(8):2220-2230.e7. doi: 10.1016/j.celrep.2019.07.082.
Although double-strand break (DSB) repair is essential for a cell's survival, little is known about how DSB repair mechanisms are affected by age. Here we characterize the impact of cellular aging on the efficiency of single-strand annealing (SSA), a DSB repair mechanism. We measure SSA repair efficiency in young and old yeast cells and report a 23.4% decline in repair efficiency. This decline is not due to increased use of non-homologous end joining. Instead, we identify increased G1 phase duration in old cells as a factor responsible for the decreased SSA repair efficiency. Expression of 3xCLN2 leads to higher SSA repair efficiency in old cells compared with expression of 1xCLN2, confirming the involvement of cell-cycle regulation in age-associated repair inefficiency. Examining how SSA repair efficiency is affected by sequence heterology, we find that heteroduplex rejection remains high in old cells. Our work provides insights into the links between single-cell aging and DSB repair efficiency.
虽然双链断裂（DSB）修复对于细胞的生存至关重要，但人们对 DSB 修复机制如何受到年龄的影响知之甚少。在这里，我们描述了细胞衰老对单链退火（SSA）这一 DSB 修复机制效率的影响。我们测量了年轻和年老酵母细胞中的 SSA 修复效率，并报告修复效率下降了 23.4%。这种下降不是由于非同源末端连接的增加所致。相反，我们发现老年细胞 G1 期持续时间增加是导致 SSA 修复效率下降的一个因素。与表达 1xCLN2 相比，表达 3xCLN2 可使老年细胞中的 SSA 修复效率提高，这证实了细胞周期调控参与了与年龄相关的修复效率降低。通过研究 SSA 修复效率如何受到序列异质性的影响，我们发现异源双链体的排斥在老年细胞中仍然很高。我们的工作为单细胞衰老与 DSB 修复效率之间的联系提供了新的认识。
