Identification of the promoter region of the Xanthomonas campestris pv. citri recA gene responsible for induction by DNA-damaging agents

The abundance of the RecA protein and of recA transcripts was markedly incr eased on exposure of Xanthomonas campestris pathovar citri to various DNA-d amaging agents, including mitomycin C. The promoter sequence responsible fo r mediating the sensitivity of recA expression to DNA damage was investigat ed by subcloning a 426-bp restriction fragment of the 5' untranslated and c oding region of the gene into a promoterless vector containing the luxAB ge nes of Vibrio fischeri. Xanthomonas campestris pv. citri cells transformed with this vector responded to DNA-damaging agents with a marked increase in luciferase activity. Deletion of nucleotides from the 5' end of the recA f ragment inserted into the reporter plasmid revealed that the 58 bp upstream of the transcription initiation site are sufficient to mediate induction o f uecA expression by mitomycin C. (C) 1999 Federation of European Microbiol ogical Societies. Published by Elsevier Science B.V. All rights reserved.