PMID:19376866

Citation	Gaasbeek, EJ, van der Wal, FJ, van Putten, JP, de Boer, P, van der Graaf-van Bloois, L, de Boer, AG, Vermaning, BJ and Wagenaar, JA (2009) Functional characterization of excision repair and RecA-dependent recombinational DNA repair in Campylobacter jejuni. J. Bacteriol. 191:3785-93
Abstract	The presence and functionality of DNA repair mechanisms in Campylobacter jejuni are largely unknown. In silico analysis of the complete translated genome of C. jejuni NCTC 11168 suggests the presence of genes involved in methyl-directed mismatch repair (MMR), nucleotide excision repair, base excision repair (BER), and recombinational repair. To assess the functionality of these putative repair mechanisms in C. jejuni, mutS, uvrB, ung, and recA knockout mutants were constructed and analyzed for their ability to repair spontaneous point mutations, UV irradiation-induced DNA damage, and nicked DNA. Inactivation of the different putative DNA repair genes did not alter the spontaneous mutation frequency. Disruption of the UvrB and RecA orthologues, but not the putative MutS or Ung proteins, resulted in a significant reduction in viability after exposure to UV irradiation. Assays performed with uracil-containing plasmid DNA showed that the putative uracil-DNA glycosylase (Ung) protein, important for initiation of the BER pathway, is also functional in C. jejuni. Inactivation of recA also resulted in a loss of natural transformation. Overall, the data indicate that C. jejuni has multiple functional DNA repair systems that may protect against DNA damage and limit the generation of genetic diversity. On the other hand, the apparent absence of a functional MMR pathway may enhance the frequency of on-and-off switching of phase variable genes typical for C. jejuni and may contribute to the genetic heterogeneity of the C. jejuni population.
Links	PubMed PMC2698403 Online version:10.1128/JB.01817-08
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Campylobacter jejuni/enzymology; Campylobacter jejuni/genetics; Campylobacter jejuni/radiation effects; DNA Damage/radiation effects; DNA Repair; DNA Repair Enzymes/genetics; DNA Repair Enzymes/metabolism; Microbial Viability/radiation effects; Mutation; Rec A Recombinases/genetics; Rec A Recombinases/metabolism; Recombination, Genetic; Ultraviolet Rays
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CAMJE:RECA	involved_in	GO:0006281: DNA repair	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
CAMJE:RECA		GO:0006281: DNA repair	ECO:0000315:		P		Fig. 2 A and D. Campylobacter jejuni NCTC-11168 RecA mutants exhibit reduced viability in response to UV exposure (0.12 J cm-2 and 1.0 J cm-2) as compared to the parental strain.	complete CACAO 7187

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