Previous Article | Next Article ![]()
J. Bacteriol., 10 1997, 6244-6253, Vol 179, No. 20
M Ogura, Y Ohshiro, S Hirao and T Tanaka
Bacillus subtilis degR, a positive regulator of the production of
degradative enzymes, is negatively regulated by the competence
transcription factor ComK which is overproduced in mecA null mutants. We
used transposon Tn10 to search for a mutation that reduced the repression
level of degR caused by a mecA mutation. A new gene exerting positive
regulation on comK was obtained and designated med (suppressor of mecA
effect on degR). Sequence determination, Northern analysis, and primer
extension analyses revealed that the med gene contained an open reading
frame (ORF) composed of 317 codons and was transcribed into an
approximately 1,250-nucleotide mRNA together with its short downstream
gene. The expression of comK is positively regulated by factors such as
ComK itself, ComS (SrfA)-MecA, DegU, SinR, and AbrB. Quantitative analyses
using comK'-'lacZ, srfA-lacZ, degU'-'lacZ, and sinR'-'lacZ fusions showed
that disruption of med caused a significant decrease in comK expression in
both mecA+ and mecA strains, while expression of srfA, sinR, and degU was
not affected by the mutation. An epistatic analysis revealed that
overproduction of ComK resulted in alteration of med expression, suggesting
a regulatory loop between comK and med. Several possible mechanisms for
positive regulation of comK by Med are discussed.
Copyright © 1997, American Society for Microbiology
A new Bacillus subtilis gene, med, encodes a positive regulator of comK
School of Marine Science and Technology, Tokai University, Shimizu, Shizuoka, Japan.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»