TITLE	Construction and characterization of a recA mutant of Xanthomonas campestris pv. citri
AUTHOR	Yen-Chun Yang Department of Biology, Fu Jen University, 510 Chun-Chen Road, Taipei 242, Taiwan, Republic of China Mei-Kwei Yang Department of Biology, Fu Jen University, 510 Chun-Chen Road, Taipei 242, Taiwan, Republic of China
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ABSTRACT	The recA gene of Xanthomonas campestris pathovar citri (X. c. pv. citri) was cloned and sequenced. Nucleotide sequence analysis revealed an open reading frame of 1,032 bp that encodes a 344-amino acid protein and which shows a high degree of homology to recA genes from other bacteria. The cloned recA gene of X. c. pv. citri restored to a recA deletion mutant of Escherichia coli the ability to resist killing induced by methylmethane sulfonate or ultraviolet radiation, indicating that the cloned gene was functional in E. coli. A recA mutant of X. c. pv. citri was constructed by gene replacement and was shown both not to possess detectable DNA recombination activity and to be markedly more sensitive to DNA-damaging agents than is wild-type X. c. pv. citri. Transformation of recA mutants of E. coli and X. c. pv. citri with a plasmid containing X. c. pv. citri recA conferred the ability to produce a 37-kDa protein that reacted with antiserum to E. coli RecA protein. Two additional open reading frames were also identified in the recA region of the X. c. pv. citri genome: One located immediately upstream from recA that encodes a 213-amino acid protein with a high degree of similarity to the LexA protein of E. coli, and another located immediately downstream of recA that encodes a 153-amino acid protein with sequence similarity to the RecX protein of Pseudomonas aeruginosa.
KEYWORD	Complementation; DNA repair; Homologous recombination; RecA;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 41 Number 2 April 2000, page 129-137, 9 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China