The recX gene product is involved in the SOS response in Herbaspirillum seropedicae.
The recA and the recX genes of Herbaspirillum seropedicae were sequenced. The recX is located 359 bp downstream from recA. Sequence analysis indicated the presence of a putative operator site overlapping a probable sigma70-dependent promoter upstream of recA and a transcription terminator downstream from recX, with no apparent promoter sequence in the intergenic region. Transcriptional analysis using lacZ promoter fusions indicated that recA expression increased three- to fourfold in the presence of methyl methanesulfonate (MMS). The roles of recA and recX genes in the SOS response were determined from studies of chromosomal mutants. The recA mutant showed the highest sensitivity to MMS and UV, and the recX mutant had an intermediate sensitivity, compared with the wild type (SMR1), confirming the essential role of the RecA protein in cell viability in the presence of mutagenic agents and also indicating a role for RecX in the SOS response.
Galvão
Carolina W
CW
Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, C.P. 19046, 81531-990, Curitiba, PR, Brazil.
Pedrosa
Fábio O
FO
Souza
Emanuel M
EM
Yates
M Geoffrey
MG
Chubatsu
Leda S
LS
Steffens
Maria Berenice R
MB
D001426:Bacterial Proteins / Q000502:physiology*; D020562:Betaproteobacteria / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D015169:Colony Count, Microbial; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D008957:Models, Genetic; D009586:Nitrogen Fixation; D013014:SOS Response, Genetics / Q000235:genetics / Q000502:physiology*; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; C430523:RecX protein, Xanthomonas campestris; D008741:Methyl Methanesulfonate