title: Conservation and diversity of the IrrE/DdrO-controlled radiation response in radiation-resistant Deinococcus bacteria.
abstract: The extreme radiation resistance of Deinococcus bacteria requires the radiation-stimulated cleavage of protein DdrO by a specific metalloprotease called IrrE. DdrO is the repressor of a predicted radiation/desiccation response (RDR) regulon, composed of radiation-induced genes having a conserved DNA motif (RDRM) in their promoter regions. Here, we showed that addition of zinc ions to purified apo-IrrE, and short exposure of Deinococcus cells to zinc ions, resulted in cleavage of DdrO in vitro and in vivo, respectively. Binding of IrrE to RDRM-containing DNA or interaction of IrrE with DNA-bound DdrO was not observed. The data are in line with IrrE being a zinc peptidase, and indicate that increased zinc availability, caused by oxidative stress, triggers the in vivo cleavage of DdrO unbound to DNA. Transcriptomics and proteomics of Deinococcus deserti confirmed the IrrE-dependent regulation of predicted RDR regulon genes and also revealed additional members of this regulon. Comparative analysis showed that the RDR regulon is largely well conserved in Deinococcus species, but also showed diversity in the regulon composition. Notably, several RDR genes with an important role in radiation resistance in Deinococcus radiodurans, for example pprA, are not conserved in some other radiation-resistant Deinococcus species.
authors.affiliation: Lab Bioenerget Cellulaire, CEA, DRF, BIAM, Saint-Paul-lez-Durance, France.|CNRS, UMR 7265 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, France.|Aix-Marseille Université, Saint-Paul-lez-Durance, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Blanchard
authors.affiliation: Laboratory "Innovative technologies for Detection and Diagnostic", CEA-Marcoule, DRF/IBITEC-S/SPI/Li2D, Bagnols-sur-Cèze, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Guérin
authors.affiliation: CEA, DRF, Institut de Génomique, LABGeM, Evry, France.|UMR-CNRS 8030 Génomique Métabolique, CEA Institut de Génomique - Genoscope, Evry, France.
authors.forename: David
authors.initials: D
authors.lastname: Roche
authors.affiliation: CEA, DRF, Institut de Génomique, LABGeM, Evry, France.|UMR-CNRS 8030 Génomique Métabolique, CEA Institut de Génomique - Genoscope, Evry, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Cruveiller
authors.affiliation: Lab Bioenerget Cellulaire, CEA, DRF, BIAM, Saint-Paul-lez-Durance, France.|CNRS, UMR 7265 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, France.|Aix-Marseille Université, Saint-Paul-lez-Durance, France.
authors.forename: David
authors.initials: D
authors.lastname: Pignol
authors.affiliation: CEA, DRF, Institut de Génomique, LABGeM, Evry, France.|UMR-CNRS 8030 Génomique Métabolique, CEA Institut de Génomique - Genoscope, Evry, France.
authors.forename: David
authors.initials: D
authors.lastname: Vallenet
authors.affiliation: Laboratory "Innovative technologies for Detection and Diagnostic", CEA-Marcoule, DRF/IBITEC-S/SPI/Li2D, Bagnols-sur-Cèze, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Armengaud
authors.affiliation: Lab Bioenerget Cellulaire, CEA, DRF, BIAM, Saint-Paul-lez-Durance, France.|CNRS, UMR 7265 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance, France.|Aix-Marseille Université, Saint-Paul-lez-Durance, France.
authors.forename: Arjan
authors.identifier: 0000-0003-2202-5279
authors.initials: A
authors.lastname: de Groot
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D034301:Deinococcus / Q000145:classification / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects*; D015964:Gene Expression Regulation, Bacterial; D014644:Genetic Variation; D045726:Metalloproteases / Q000235:genetics / Q000378:metabolism; D018085:Regulon; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; D045726:Metalloproteases
keywords: gene regulation; proteomics; regulon; transcriptional repressor; transcriptomics; zinc peptidase