Involvement of an X family DNA polymerase in double-stranded break repair in the radioresistant organism Deinococcus radiodurans

Mol Microbiol. 2004 Sep;53(6):1721-30. doi: 10.1111/j.1365-2958.2004.04233.x.


DNA polymerases of the X family have been implicated in a variety of DNA repair processes in eukaryotes. Here we show that Deinococcus radiodurans, a highly radioresistant bacterium able to mend hundreds of radiation-induced double-stranded DNA breaks, expresses a DNA polymerase belonging to the X family. This novel bacterial polymerase, named PolX(Dr), was identified as the product of the Deinococcal DR0467 gene. The purified PolX(Dr) protein possesses a DNA polymerase activity that is stimulated by MnCl2, a property of the X family DNA polymerases. Antibodies raised against PolX(Dr) recognized human pol lambda, rat pol beta and yeast Pol4 and, conversely, antibodies raised against these proteins recognized PolX(Dr). This immunological cross-reactivity suggests a high degree of structural conservation among the polymerases of the X family. Lack of PolX(Dr) reduced the rate of repair of double-stranded DNA breaks and increased cell sensitivity to gamma-rays. PolX(Dr) thus appears to play an important role in double-stranded DNA break repair in D. radiodurans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / classification
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cell Division
  • DNA Repair*
  • DNA-Directed DNA Polymerase / classification
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / metabolism*
  • Deinococcus / enzymology*
  • Deinococcus / genetics*
  • Deinococcus / radiation effects
  • Gamma Rays
  • Genome, Bacterial
  • Humans
  • Rats
  • Sequence Homology, Nucleic Acid
  • Ultraviolet Rays


  • Bacterial Proteins
  • DNA-Directed DNA Polymerase