The SOS response of Listeria monocytogenes is involved in stress resistance and mutagenesis.
The SOS response is a conserved pathway that is activated under certain stress conditions and is regulated by the repressor LexA and the activator RecA. The food-borne pathogen Listeria monocytogenes contains RecA and LexA homologues, but their roles in Listeria have not been established. In this study, we identified the SOS regulon in L. monocytogenes by comparing the transcription profiles of a wild-type strain and a DeltarecA mutant strain after exposure to the DNA-damaging agent mitomycin C. In agreement with studies in other bacteria, we identified an imperfect palindrome AATAAGAACATATGTTCGTTT as the SOS operator sequence. The SOS regulon of L. monocytogenes consists of 29 genes in 16 LexA-regulated operons, encoding proteins with functions in translesion DNA synthesis and DNA repair. We furthermore identified a role for the product of the LexA-regulated gene yneA in cell elongation and inhibition of cell division. As anticipated, RecA of L. monocytogenes plays a role in mutagenesis; DeltarecA cultures showed considerably lower rifampicin- and streptomycin-resistant fractions than the wild-type cultures. The SOS response is activated after stress exposure as shown by recA- and yneA-promoter reporter studies. Stress-survival studies showed DeltarecA mutant cells to be less resistant to heat, H(2)O(2) and acid exposure than wild-type cells. Our results indicate that the SOS response of L. monocytogenes contributes to survival upon exposure to a range of stresses, thereby likely contributing to its persistence in the environment and in the host.
van der Veen
Stijn
S
Laboratory of Food Microbiology, Wageningen University and Research Centre, Bomenweg 2, 6703 HD Wageningen, The Netherlands.|Division of Health and Safety, NIZO Food Research, Kernhemseweg 2, 6718 ZB Ede, The Netherlands.|Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands.
van Schalkwijk
Saskia
S
Division of Health and Safety, NIZO Food Research, Kernhemseweg 2, 6718 ZB Ede, The Netherlands.|Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands.
Molenaar
Douwe
D
Division of Health and Safety, NIZO Food Research, Kernhemseweg 2, 6718 ZB Ede, The Netherlands.|Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands.
de Vos
Willem M
WM
Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands.
Abee
Tjakko
T
Laboratory of Food Microbiology, Wageningen University and Research Centre, Bomenweg 2, 6703 HD Wageningen, The Netherlands.|Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands.
Wells-Bennik
Marjon H J
MHJ
Division of Health and Safety, NIZO Food Research, Kernhemseweg 2, 6718 ZB Ede, The Netherlands.|Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands.
D002455:Cell Division / Q000187:drug effects; D004249:DNA Damage; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial / Q000187:drug effects; D008089:Listeria monocytogenes / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D016685:Mitomycin / Q000494:pharmacology; D016296:Mutagenesis / Q000187:drug effects; D011938:Rec A Recombinases / Q000502:physiology; D018085:Regulon / Q000187:drug effects; D013014:SOS Response, Genetics / Q000187:drug effects / Q000235:genetics; D013312:Stress, Physiological
D004269:DNA, Bacterial; D016685:Mitomycin; D011938:Rec A Recombinases