The Escherichia coli replisome is inherently DNA damage tolerant

Science. 2011 Oct 14;334(6053):235-8. doi: 10.1126/science.1209111.

Abstract

The Escherichia coli DNA replication machinery must frequently overcome template lesions under normal growth conditions. Yet, the outcome of a collision between the replisome and a leading-strand template lesion remains poorly understood. Here, we demonstrate that a single, site-specific, cyclobutane pyrimidine dimer leading-strand template lesion provides only a transient block to fork progression in vitro. The replisome remains stably associated with the fork after collision with the lesion. Leading-strand synthesis is then reinitiated downstream of the damage in a reaction that is dependent on the primase, DnaG, but independent of any of the known replication-restart proteins. These observations reveal that the replisome can tolerate leading-strand template lesions without dissociating by synthesizing the leading strand discontinuously.

Publication types

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

MeSH terms

  • DNA Damage*
  • DNA Polymerase III / metabolism
  • DNA Primase
  • DNA Replication*
  • DNA, Bacterial / biosynthesis*
  • DNA-Directed DNA Polymerase / metabolism*
  • Endodeoxyribonucleases / metabolism
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / metabolism*
  • Exodeoxyribonucleases / metabolism
  • Multienzyme Complexes / metabolism*
  • Plasmids
  • Pyrimidine Dimers
  • Replication Origin
  • Templates, Genetic

Substances

  • DNA, Bacterial
  • Escherichia coli Proteins
  • Multienzyme Complexes
  • Pyrimidine Dimers
  • DNA Primase
  • DNA synthesome
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • Endodeoxyribonucleases
  • Exodeoxyribonucleases
  • dnaG protein, E coli