Construction and Characterization of a recA Mutant of Xanthomonas campestris pv. citri

柑橘潰瘍病菌recA突變株之建立與特性分析

楊源昌(Yen-Chun Yang) ； 楊美桂(Mei-Kwei Yang)

《Botanical Bulletin of Academia Sinica》 41卷2期 (2000/04) Pp. 129-137

https://doi.org/10.7016/BBAS.200004.0129

摘要

自柑橘潰瘍病菌(Xanthomonas campestris pv.citri)所選殖之recA基因，是由1032個核苷酸所組成，可合成含344个氨基酸之蛋白质。其序列与其他细菌之recA基因很類似，合成之蛋白在大腸桿菌內亦具有功能。利用插入性突變法，得到recA突變株，對DNA突變劑極為敏感，也失去基因重組的能力選殖之recA基因，可形成一37kDa之蛋白，可與抗大腸菌RecA之抗體作用。另外，在recA基因之上游還發現一可產生213氨基酸之蛋白的基因，相似於大腸桿菌之lexA基因；而在其下游，還有一由153氨基酸所組成之蛋白之基因，相當於綠膿桿菌之recX基因。

關鍵字

基因重組 ； RecA ； 互補 ； DNA修補

並列摘要

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.

並列關鍵字

Complementation ； DNA repair ； Homologous recombination ； RecA.