Characterization of an lrp-like (lrpC) gene from Bacillus subtilis.
In the course of the Bacillus subtilis genome sequencing project, we identified an open reading frame encoding a putative 16.4 kDa protein. This protein shows, respectively, 34% and 25% identity with the Escherichia coli regulatory proteins Lrp and AsnC. Phylogenetic analysis suggests that it represents a new group in the AsnC-Lrp family. Sequence comparisons, as well as immunodetection experiments, lead to the conclusion that the product of this B. subtilis lrp-like-gene is a bona fide Lrp protein-the first one to be detected in gram-positive bacteria. When expressed in E. coli, the B. subtilis Lrp-like protein is able to repress, by about two-fold, the expression of the ilvIH operon which is normally regulated by E. coli Lrp, indicating functional similarity in their regulatory targets. Vegetative growth of a B. subtilis lrp-like mutant is not affected in rich medium. However, the lrp-like mutation causes a transitory inhibition of growth in minimal medium in the presence of valine and isoleucine, which is relieved by leucine. This points to a possible role in regulation of amino acid metabolism. In addition, sporogenesis occurs earlier in the lrp-like mutant than in the reference strain, implying that the B subtilis Lrp-like protein plays a role in the growth phase transition.
Beloin
C
C
Institut de Génétique et Microbiologie, Université Paris XI, Orsay, France.
Ayora
S
S
Exley
R
R
Hirschbein
L
L
Ogasawara
N
N
Kasahara
Y
Y
Alonso
J C
JC
Hégarat
F L
FL
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006358:Hot Temperature; D007763:Lac Operon / Q000235:genetics; D051756:Leucine-Responsive Regulatory Protein; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D009876:Operon; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013171:Spores, Bacterial / Q000502:physiology; D014157:Transcription Factors; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C497278:Lrp protein, E coli; D014157:Transcription Factors; D051756:Leucine-Responsive Regulatory Protein; D001616:beta-Galactosidase