Overproduction of the RecD polypeptide sensitizes Escherichia coli cells to gamma-radiation

Mutat Res. 1992 Feb;281(2):123-7. doi: 10.1016/0165-7992(92)90046-k.


We investigated DNA metabolism in Escherichia coli cells carrying the multicopy recD+ plasmid (pKI13). In the presence of pKI13, the cellular level of the recD gene product (RecD polypeptide) is amplified at least 60-fold. Overproduction of the RecD polypeptide has no effect on UV repair and conjugational recombination. In contrast, high cellular levels of this polypeptide sensitize wild-type cells to gamma-radiation; also, they increase the rate of radiation-induced DNA degradation. A possible mechanism for the enhancement of gamma-ray-induced killing by large amounts of the RecD polypeptide is discussed.

MeSH terms

  • DNA Repair / genetics*
  • DNA, Bacterial / metabolism
  • Dose-Response Relationship, Radiation
  • Escherichia coli / genetics
  • Escherichia coli / radiation effects*
  • Escherichia coli Proteins*
  • Exodeoxyribonuclease V
  • Exodeoxyribonucleases / genetics*
  • Gamma Rays
  • Gene Expression / genetics
  • Kinetics
  • Plasmids / genetics
  • Recombination, Genetic / genetics
  • Ultraviolet Rays


  • DNA, Bacterial
  • Escherichia coli Proteins
  • Exodeoxyribonucleases
  • Exodeoxyribonuclease V
  • exodeoxyribonuclease V, E coli