期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 288, 期 46, 页码 33193-33204出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M113.496133
关键词
DNA Damage; DNA Replication; DNA Topoisomerase; DNA Topology; Homologous Recombination; Holliday Junction; Rec-X; Sgs1; Template Switch Recombination; Top3
资金
- National Institutes of Health from the NCI [R25 CA101871]
- [sT32-AG000255]
- [R01-GM071268]
- [R01-AG021521]
- [P01-AG031862]
Background: The Sgs1/Top3/Rmi1 (STR) complex resolves DNA linkages formed during replication of methyl methanesulfonate (MMS)-damaged templates. Results: Even without Sgs1 and Rmi1, Top3 can provide some resistance to MMS and resolve linkages that have recombination-dependent X-molecule (Rec-X) topology. Conclusion: Rec-Xs form during replication of MMS-damaged DNA. Significance: The findings provide novel insight into replication, STR function, and genome maintenance. The evolutionarily conserved Sgs1/Top3/Rmi1 (STR) complex plays vital roles in DNA replication and repair. One crucial activity of the complex is dissolution of toxic X-shaped recombination intermediates that accumulate during replication of damaged DNA. However, despite several years of study the nature of these X-shaped molecules remains debated. Here we use genetic approaches and two-dimensional gel electrophoresis of genomic DNA to show that Top3, unassisted by Sgs1 and Rmi1, has modest capacities to provide resistance to MMS and to resolve recombination-dependent X-shaped molecules. The X-shaped molecules have structural properties consistent with hemicatenane-related template switch recombination intermediates (Rec-Xs) but not Holliday junction (HJ) intermediates. Consistent with these findings, we demonstrate that purified Top3 can resolve a synthetic Rec-X but not a synthetic double HJ in vitro. We also find that unassisted Top3 does not affect crossing over during double strand break repair, which is known to involve double HJ intermediates, confirming that unassisted Top3 activities are restricted to substrates that are distinct from HJs. These data help illuminate the nature of the X-shaped molecules that accumulate during replication of damaged DNA templates, and also clarify the roles played by Top3 and the STR complex as a whole during the resolution of replication-associated recombination intermediates.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据