美国马萨诸塞大学医学院Phillip D. Zamore团队发现,嗜热栖热菌Argonaute在DNA复制中的功能。这一研究成果于2020年8月25日在线发表在国际学术期刊《细胞》上。
据研究人员介绍,在许多真核生物中,由短RNA序列引导的Argonaute蛋白可以防御转座子和病毒。在真细菌嗜热栖热菌中,DNA引导的Argonaute蛋白TtAgo可以防御DNA质粒的转化。
Title: Thermus thermophilus Argonaute Functions in the Completion of DNA Replication
Author: Samson M. Jolly, Ildar Gainetdinov, Karina Jouravleva, Han Zhang, Lara Strittmatter, Shannon M. Bailey, Gregory M. Hendricks, Avantika Dhabaria, Beatrix Ueberheide, Phillip D. Zamore
Issue&Volume: 2020-08-25
Abstract: In many eukaryotes, Argonaute proteins, guided by short RNA sequences, defend cellsagainst transposons and viruses. In the eubacterium Thermus thermophilus, the DNA-guided Argonaute TtAgo defends against transformation by DNA plasmids. Here,we report that TtAgo also participates in DNA replication. In vivo, TtAgo binds 15- to 18-nt DNA guides derived from the chromosomal region where replicationterminates and associates with proteins known to act in DNA replication. When gyrase,the sole T. thermophilus type II topoisomerase, is inhibited, TtAgo allows the bacterium to finish replicatingits circular genome. In contrast, loss of gyrase and TtAgo activity slows growth andproduces long sausage-like filaments in which the individual bacteria are linked byDNA. Finally, wild-type T. thermophilus outcompetes an otherwise isogenic strain lacking TtAgo. We propose that the primaryrole of TtAgo is to help T. thermophilus disentangle the catenated circular chromosomes generated by DNA replication.
DOI: 10.1016/j.cell.2020.07.036
Source: https://www.cell.com/cell/fulltext/S0092-8674(20)30944-2