论文
论文标题：Error-prone, stress-induced 3′ flap–based Okazaki fragment maturation supports cell survival
作者：Haitao Sun, Zhaoning Lu, Amanpreet Singh, Yajing Zhou, Eric Zheng, Mian Zhou, Jinhui Wang, Xiwei Wu, Zunsong Hu, Zhaohui Gu, Judith L. Campbell, Li Zheng, Binghui Shen
期刊：Science
发表时间：2021/12/03
数字识别码：10.1126/science.abj1013
摘要：How cells with DNA replication defects acquire mutations that allow them to escape apoptosis under environmental stress is a long-standing question. Here, we report that an error-prone Okazaki fragment maturation (OFM) pathway is activated at restrictive temperatures in rad27Δ yeast cells. Restrictive temperature stress activated Dun1, facilitating transformation of unprocessed 5′ flaps into 3′ flaps, which were removed by 3′ nucleases, including DNA polymerase δ (Polδ). However, at certain regions, 3′ flaps formed secondary structures that facilitated 3′ end extension rather than degradation, producing alternative duplications with short spacer sequences, such as pol3 internal tandem duplications. Consequently, little 5′ flap was formed, suppressing rad27Δ-induced lethality at restrictive temperatures. We define a stress-induced, error-prone OFM pathway that generates mutations that counteract replication defects and drive cellular evolution and survival.
