The RecBC enzyme loads recA protein onto ssDNA asymmetrically and independently of χ, resulting in constitutive recombination activation

Jason J. Churchill, Daniel G. Anderson, Stephen C. Kowalczykowski

Research output: Contribution to journalArticlepeer-review

99 Scopus citations

Abstract

Double-strand DNA break repair and homologous recombination in Escherichia coil proceed by the RecBCD pathway, which is regulated by cis- acting elements known as χ sites. A crucial feature of this regulation is the RecBCD enzyme-directed loading of RecA protein specifically onto the 3'- terminal, χ-containing DNA strand. Here we show that RecBC enzyme (lacking the RecD subunit) loads RecA protein constitutively onto the 3'-terminal DNA strand, with no requirement for χ. This strand is preferentially utilized in homologous pairing reactions. We propose that RecA protein loading is a latent property of the RecBCD holoenzyme, which is normally blocked by the RecD subunit and is revealed following interaction with χ.

Original languageEnglish (US)
Pages (from-to)901-911
Number of pages11
JournalGenes and Development
Volume13
Issue number7
StatePublished - Apr 1 1999

Keywords

  • χ
  • DNA repair
  • Helicase
  • RecA
  • RecBC
  • Recombination

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology

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