Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia University Irving Medical Center, New York, NY 10032, USA; Columbia University Stem Cell Initiative, New York, NY 10032, USA.
Columbia University Stem Cell Initiative, New York, NY 10032, USA; Department of Genetics and Development, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA.
Cell Rep. 2024 Apr 23;43(4):114006. doi: 10.1016/j.celrep.2024.114006. Epub 2024 Mar 30.
Reprogramming to pluripotency is associated with DNA damage and requires the functions of the BRCA1 tumor suppressor. Here, we leverage separation-of-function mutations in BRCA1/2 as well as the physical and/or genetic interactions between BRCA1 and its associated repair proteins to ascertain the relevance of homology-directed repair (HDR), stalled fork protection (SFP), and replication gap suppression (RGS) in somatic cell reprogramming. Surprisingly, loss of SFP and RGS is inconsequential for the transition to pluripotency. In contrast, cells deficient in HDR, but proficient in SFP and RGS, reprogram with reduced efficiency. Conversely, the restoration of HDR function through inactivation of 53bp1 rescues reprogramming in Brca1-deficient cells, and 53bp1 loss leads to elevated HDR and enhanced reprogramming in mouse and human cells. These results demonstrate that somatic cell reprogramming is especially dependent on repair of replication-associated double-strand breaks (DSBs) by the HDR activity of BRCA1 and BRCA2 and can be improved in the absence of 53BP1.
重编程为多能性与 DNA 损伤有关，需要 BRCA1 肿瘤抑制因子的功能。在这里，我们利用 BRCA1/2 的功能分离突变，以及 BRCA1 与其相关修复蛋白之间的物理和/或遗传相互作用，来确定同源重组修复 (HDR)、停滞叉保护 (SFP) 和复制间隙抑制 (RGS) 在体细胞重编程中的相关性。令人惊讶的是，SFP 和 RGS 的缺失对向多能性的转变没有影响。相比之下，缺乏 HDR 但具有 SFP 和 RGS 的细胞的重编程效率降低。相反，通过失活 53bp1 恢复 HDR 功能可挽救 Brca1 缺陷细胞的重编程，而 53bp1 的缺失导致 HDR 升高和小鼠和人类细胞的重编程增强。这些结果表明，体细胞重编程特别依赖于 BRCA1 和 BRCA2 的 HDR 活性修复与复制相关的双链断裂 (DSBs)，并且在没有 53BP1 的情况下可以得到改善。
