Mfd is required for rapid recovery of transcription following UV-induced DNA damage but not oxidative DNA damage in Escherichia coli

J Bacteriol. 2012 May;194(10):2637-45. doi: 10.1128/JB.06725-11. Epub 2012 Mar 16.

Abstract

Transcription-coupled repair (TCR) is a cellular process by which some forms of DNA damage are repaired more rapidly from transcribed strands of active genes than from nontranscribed strands or the overall genome. In humans, the TCR coupling factor, CSB, plays a critical role in restoring transcription following both UV-induced and oxidative DNA damage. It also contributes indirectly to the global repair of some forms of oxidative DNA damage. The Escherichia coli homolog, Mfd, is similarly required for TCR of UV-induced lesions. However, its contribution to the restoration of transcription and to global repair of oxidative damage has not been examined. Here, we report the first direct study of transcriptional recovery following UV-induced and oxidative DNA damage in E. coli. We observed that mutations in mfd or uvrA reduced the rate that transcription recovered following UV-induced damage. In contrast, no difference was detected in the rate of transcription recovery in mfd, uvrA, fpg, nth, or polB dinB umuDC mutants relative to wild-type cells following oxidative damage. mfd mutants were also fully resistant to hydrogen peroxide (H(2)O(2)) and removed oxidative lesions from the genome at rates comparable to wild-type cells. The results demonstrate that Mfd promotes the rapid recovery of gene expression following UV-induced damage in E. coli. In addition, these findings imply that Mfd may be functionally distinct from its human CSB homolog in that it does not detectably contribute to the recovery of gene expression or global repair following oxidative damage.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • DNA Damage / radiation effects*
  • DNA Repair
  • DNA, Bacterial / drug effects
  • DNA, Bacterial / radiation effects*
  • Escherichia coli / drug effects
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli / radiation effects
  • Gene Expression Regulation, Bacterial / drug effects
  • Gene Expression Regulation, Bacterial / radiation effects
  • Hydrogen Peroxide
  • Mutation
  • Oxidative Stress / drug effects*
  • RNA, Bacterial / genetics
  • RNA, Bacterial / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcription, Genetic
  • Ultraviolet Rays*

Substances

  • Bacterial Proteins
  • DNA, Bacterial
  • RNA, Bacterial
  • Transcription Factors
  • transcription repair coupling factor protein, Bacteria
  • Hydrogen Peroxide