mu insertions are repaired by the double-strand break repair pathway of escherichia coliμ插入是由双链断裂修复的修复通路的大肠杆菌.pdfVIP

Mu Insertions Are Repaired by the Double-Strand Break Repair Pathway of Escherichia coli 1 2 1 Sooin Jang , Steven J. Sandler , Rasika M. Harshey * 1 Section of Molecular Genetics and Microbiology and Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America, 2 Department of Microbiology, Morill Science Center, University of Massachusetts at Amherst, Amherst, Massachusetts, United States of America Abstract Mu is both a transposable element and a temperate bacteriophage. During lytic growth, it amplifies its genome by replicative transposition. During infection, it integrates into the Escherichia coli chromosome through a mechanism not requiring extensive DNA replication. In the latter pathway, the transposition intermediate is repaired by transposase- mediated resecting of the 59 flaps attached to the ends of the incoming Mu genome, followed by filling the remaining 5 bp gaps at each end of the Mu insertion. It is widely assumed that the gaps are repaired by a gap-filling host polymerase. Using the E. coli Keio Collection to screen for mutants defective in recovery of stable Mu insertions, we show in this study that the gaps are repaired by the machinery responsible for the repair of double-strand breaks in E. coli—the replication restart proteins PriA-DnaT and homologous recombination proteins RecABC. We discuss alternate models for recombinational repair of the Mu gaps. Citation: Jang S, Sandler SJ, Harshey RM (2012) Mu Insertions Are Repaired by the Double-Strand Break Repair Pathway of Escherichia coli. PLoS Genet 8(4): e1002642. doi:10.1371/journal.pgen.1002642 Editor: Diarmaid Hughes, Uppsala University, Sweden Received September 15, 2011; Accepted February 22, 2012;