Mu insertions are repaired by the double-strand break repair pathway of Escherichia coli

PLoS Genet. 2012;8(4):e1002642. doi: 10.1371/journal.pgen.1002642. Epub 2012 Apr 12.


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 5' 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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bacteriophage mu* / genetics
  • Bacteriophage mu* / growth & development
  • DNA Breaks, Double-Stranded
  • DNA Helicases / genetics
  • DNA Helicases / metabolism
  • DNA Repair* / genetics
  • DNA Transposable Elements / genetics*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Escherichia coli* / genetics
  • Genome
  • Homologous Recombination / genetics*
  • Mutagenesis, Insertional
  • Mutation
  • Transposases / metabolism


  • DNA Transposable Elements
  • DNA-Binding Proteins
  • DnaT protein, E coli
  • Escherichia coli Proteins
  • Transposases
  • priA protein, E coli
  • DNA Helicases