Involvement of an X family DNA polymerase in double-stranded break repair in the radioresistant organism Deinococcus radiodurans.
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.
Lecointe
François
F
Institut de Génétique et Microbiologie, Bâtiment 409, Université Paris-Sud, F-91405 Orsay Cedex, France.
Shevelev
Igor V
IV
Bailone
Adriana
A
Sommer
Suzanne
S
Hübscher
Ulrich
U
D000818:Animals; D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D034301:Deinococcus / Q000201:enzymology* / Q000235:genetics* / Q000528:radiation effects; D005720:Gamma Rays; D016680:Genome, Bacterial; D006801:Humans; D051381:Rats; D012689:Sequence Homology, Nucleic Acid; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; D004259:DNA-Directed DNA Polymerase