title: Mutagenic lesion bypass and two functionally different RecA proteins in Deinococcus deserti.
abstract: RecA is essential for extreme radiation tolerance in Deinococcus radiodurans. Interestingly, Sahara bacterium Deinococcus deserti has three recA genes (recA(C), recA(P1), recA(P3)) that code for two different RecA proteins (RecA(C), RecA(P)). Moreover, and in contrast to other sequenced Deinococcus species, D. deserti possesses homologues of translesion synthesis (TLS) DNA polymerases, including ImuY and DnaE2. Together with a lexA homologue, imuY and dnaE2 form a gene cluster similar to a widespread RecA/LexA-controlled mutagenesis cassette. After having developed genetic tools, we have constructed mutant strains to characterize these recA and TLS polymerase genes in D. deserti. Both RecA(C) and RecA(P) are functional and allow D. deserti to survive, and thus repair massive DNA damage, after exposure to high doses of radiation. D. deserti is mutable by UV, which requires ImuY, DnaE2 and RecA(C), but not RecA(P). RecA(C), but not RecA(P), facilitates induced expression of imuY and dnaE2 following UV exposure. We propose that the extra recA(P1) and recA(P3) genes may provide higher levels of RecA protein for efficient error-free repair of DNA damage, without further increasing error-prone lesion bypass by ImuY and DnaE2, whereas limited TLS may contribute to adaptation to harsh conditions by generating genetic variability.
authors.affiliation: CEA, DSV, IBEB, Lab Ecol Microb Rhizosphere & Environ Extrem (LEMiRE), Saint-Paul-lez-Durance, F-13108, France.CNRS, UMR 6191 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, F-13108, France.Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France.
authors.forename: Rémi
authors.initials: R
authors.lastname: Dulermo
authors.affiliation: CEA, DSV, IBEB, Lab Ecol Microb Rhizosphere & Environ Extrem (LEMiRE), Saint-Paul-lez-Durance, F-13108, France.CNRS, UMR 6191 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, F-13108, France.Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Fochesato
authors.affiliation: CEA, DSV, IBEB, Lab Ecol Microb Rhizosphere & Environ Extrem (LEMiRE), Saint-Paul-lez-Durance, F-13108, France.CNRS, UMR 6191 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, F-13108, France.Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Blanchard
authors.affiliation: CEA, DSV, IBEB, Lab Ecol Microb Rhizosphere & Environ Extrem (LEMiRE), Saint-Paul-lez-Durance, F-13108, France.CNRS, UMR 6191 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, F-13108, France.Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France.
authors.forename: Arjan
authors.initials: A
authors.lastname: De Groot
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics; D034301:Deinococcus / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D012697:Serine Endopeptidases / Q000378:metabolism; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011938:Rec A Recombinases; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein