Effect of chloramphenicol and the recB gene product on DNA metabolism in Escherichia coli K12 strains defective in DNA ligase

Mol Gen Genet. 1976 Aug 10;147(1):79-82. doi: 10.1007/BF00337939.


We have examined DNA strand breakage, DNA degradation, and the rate of DNA synthesis in lig and lig-recB strains of Escherichia coli K12 incubated in the presence and absence of 3 mug/ml chloramphenicol. Substantial DNA strand breakage and DNA degradation is observed in the lig strain upon growth at 40 degrees C; however, such strand breakage and DNA degradation is not observed in th lig-recB strainl Incubation of the lig strain at 40 degrees C in the presence of 3 mug/ml chloramphenicol reduces the amount of DNA strand breakage and DNA degradation to the level observed in the lig-recB strain. Together, these results demonstrate that exonuclease V (the recBC gene product) is responsible for the increased DNA degradation associated with DNA ligase deficiency.

MeSH terms

  • Chloramphenicol / pharmacology*
  • Chromosomes, Bacterial
  • DNA / biosynthesis
  • DNA Repair*
  • DNA, Bacterial / metabolism*
  • Escherichia coli / drug effects*
  • Escherichia coli / enzymology
  • Mutation
  • Polynucleotide Ligases / metabolism*
  • Transcription, Genetic


  • DNA, Bacterial
  • Chloramphenicol
  • DNA
  • Polynucleotide Ligases