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Functional characterization of excision repair and RecA-dependent recombinational DNA repair in Campylobacter jejuni.

Authors :
Gaasbeek EJ
van der Wal FJ
van Putten JP
de Boer P
van der Graaf-van Bloois L
de Boer AG
Vermaning BJ
Wagenaar JA
Source :
Journal of bacteriology [J Bacteriol] 2009 Jun; Vol. 191 (12), pp. 3785-93. Date of Electronic Publication: 2009 Apr 17.
Publication Year :
2009

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.

Details

Language :
English
ISSN :
1098-5530
Volume :
191
Issue :
12
Database :
MEDLINE
Journal :
Journal of bacteriology
Publication Type :
Academic Journal
Accession number :
19376866
Full Text :
https://doi.org/10.1128/JB.01817-08