Interspecies regulation of the recA gene of gram-negative bacteria lacking an E. coli-like SOS operator.
The recA genes of Agrobacterium tumefaciens, Rhizobium meliloti, Rhizobium phaseoli and Rhodobacter sphaeroides, species belonging to the alpha-group bacteria of the Proteobacteria class, have been fused in vitro to the lacZ gene of Escherichia coli. By using a mini-Tn5 transposon derivative, each of these recA-lacZ fusions was introduced into the chromosome of each of the four species, and into that of E. coli. The recA genes of three of the alpha bacteria are induced by DNA damage when inserted in A. tumefaciens, R. phaseoli or R. meliloti chromosomes. The expression of the recA gene of R. sphaeroides is DNA damage-mediated only when present in its own chromosome; none of the genes is induced in E. coli. Likewise, the recA gene of E. coli is not induced in any of the four alpha species. These data indicate that A. tumefaciens, R. meliloti and R. phaseoli possess a LexA-like repressor, which is able to block the expression of their recA genes, as well as that of R. sphaeroides, but not the recA gene of E. coli. The LexA repressor of R. sphaeroides does not repress the recA gene of A. tumefaciens, R. meliloti, R. phaseoli or E. coli.
Riera
J
J
Department of Genetics and Microbiology, Faculty of Sciences, Autonomous University of Barcelona, Spain.
Fernández de Henestrosa
A R
AR
Garriga
X
X
Tapias
A
A
Barbé
J
J
D016960:Agrobacterium tumefaciens / Q000235:genetics; D001426:Bacterial Proteins / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D006090:Gram-Negative Bacteria / Q000235:genetics*; D007763:Lac Operon; D011401:Promoter Regions, Genetic; D011938:Rec A Recombinases / Q000096:biosynthesis / Q000235:genetics*; D012231:Rhizobium / Q000235:genetics; D012242:Rhodobacter sphaeroides / Q000235:genetics; D013014:SOS Response, Genetics / Q000235:genetics*; D012697:Serine Endopeptidases; D016962:Sinorhizobium meliloti / Q000235:genetics; D013045:Species Specificity; D000099160:LexA Repressor Protein
D001426:Bacterial Proteins; D011938:Rec A Recombinases; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein