J. Bacteriol., 02 1996, 951-960, Vol 178, No. 4
Copyright © 1996, American Society for Microbiology

Genetic evidence for an activator required for induction of colicin- like bacteriocin 28b production in Serratia marcescens by DNA-damaging agents

S Ferrer, MB Viejo, JF Guasch, J Enfedaque and M Regue
Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Barcelona, Spain.

Bacteriocin 28b production is induced by mitomycin in wild-type Serratia marcescens 2170 but not in Escherichia coli harboring the bacteriocin 28b structural gene (bss). Studies with a bss-lacZ transcriptional fusion showed that mitomycin increased the level of bss gene transcription in S. marcescens but not in the E. coli background. A S. marcescens Tn5 insertion mutant was obtained (S. marcescens 2170 reg::Tn5) whose bacteriocin 28b production and bss gene transcription were not increased by mitomycin treatment. Cloning and DNA sequencing of the mutated region showed that the Tn5 insertion was flanked by an SOS box sequence and three genes that are probably cotranscribed (regA, regB, and regC). These three genes had homology to phage holins, phage lysozymes, and the Ogr transcriptional activator of P2 and related bacteriophages, respectively. Recombinant plasmid containing this wild- type DNA region complemented the reg::Tn5 regulatory mutant. A transcriptional fusion between a 157-bp DNA fragment, containing the apparent SOS box upstream of the regA gene, and the cat gene showed increased chloramphenicol acetyltransferase activity upon mitomycin treatment. Upstream of the bss gene, a sequence similar to the consensus sequence proposed to bind Ogr protein was found, but no sequence similar to an SOS box was detected. Our results suggest that transcriptional induction of bacteriocin 28b upon mitomycin treatment is mediated by the regC gene whose own transcription would be LexA dependent.

This article has been cited by other articles:

• Cascales, E., Buchanan, S. K., Duche, D., Kleanthous, C., Lloubes, R., Postle, K., Riley, M., Slatin, S., Cavard, D. (2007). Colicin Biology. Microbiol. Mol. Biol. Rev. 71: 158-229 [Abstract] [Full Text]  
• McAlister, V., Zou, C., Winslow, R. H., Christie, G. E. (2003). Purification and In Vitro Characterization of the Serratia marcescens NucC Protein, a Zinc-Binding Transcription Factor Homologous to P2 Ogr. J. Bacteriol. 185: 1808-1816 [Abstract] [Full Text]  
• Seo, J.-W., Jang, K.-H., Kang, S. A., Song, K.-B., Jang, E. K., Park, B.-S., Kim, C. H., Rhee, S.-K. (2002). Molecular Characterization of the Growth Phase-Dependent Expression of the lsrA Gene, Encoding Levansucrase of Rahnella aquatilis. J. Bacteriol. 184: 5862-5870 [Abstract] [Full Text]  
• Walker, S. A., Klaenhammer, T. R. (2001). Leaky Lactococcus Cultures That Externalize Enzymes and Antigens Independently of Culture Lysis and Secretion and Export Pathways. Appl. Environ. Microbiol. 67: 251-259 [Abstract] [Full Text]  
• Saigí, F., Climent, N., Piqué, N., Sanchez, C., Merino, S., Rubirés, X., Aguilar, A., Tomás, J. M., Regué, M. (1999). Genetic Analysis of the Serratia marcescens N28b O4 Antigen Gene Cluster. J. Bacteriol. 181: 1883-1891 [Abstract] [Full Text]  
• Winslow, R. H., Julien, B., Calendar, R., Christie, G. E. (1998). An Upstream Sequence Element Required for NucC-Dependent Expression of the Serratia marcescens Extracellular Nuclease. J. Bacteriol. 180: 6064-6067 [Abstract] [Full Text]  
• Guynn, L. J., Dai, W., Benedik, M. J. (1998). Nuclease Overexpression Mutants of Serratia marcescens. J. Bacteriol. 180: 2262-2264 [Abstract] [Full Text]