The leucine-responsive regulatory protein of Escherichia coli negatively regulates transcription of ompC and micF and positively regulates translation of ompF.
AUTOR(ES)
Ferrario, M
RESUMO
The two major porins of Escherichia coli K-12 strains, OmpC and OmpF, are inversely regulated with respect to one another. The expression of OmpC and OmpF has been shown to be influenced by the leucine-responsive regulatory protein (Lrp): two-dimensional gel electrophoresis of proteins from strains with and strains without a functional Lrp protein revealed that OmpC expression is increased in an lrp strain, while OmpF expression is decreased. In agreement with these findings, we now present evidence that transcriptional (operon) fusions of lacZ+ to ompC and micF are negatively regulated by Lrp. Lrp binds specifically to the intergenic region between micF and ompC, as indicated by mobility shift assays and by DNase I footprinting. The expression of an ompF'-lacZ+ gene (translational) fusion is increased 3.7-fold in an lrp+ background compared with an lrp background, but expression of an ompF-lacZ+ operon fusion is not. Studies of in vivo expression of the outer membrane porins during growth on glucose minimal medium showed that the OmpF/OmpC ratio is higher in lrp+ strains than it is in isogenic lrp strains. The effect of Lrp was not seen in a strain containing a deletion of micF. Our studies suggest that the positive effect of Lrp on OmpF expression stems from a negative effect of Lrp on the expression of micF, an antisense RNA that inhibits ompF translation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=176562Documentos Relacionados
- H-NS regulates OmpF expression through micF antisense RNA in Escherichia coli.
- micF antisense RNA has a major role in osmoregulation of OmpF in Escherichia coli.
- Role of lipopolysaccharide in assembly of Escherichia coli outer membrane proteins OmpA, OmpC, and OmpF.
- Lactoferrin binds to porins OmpF and OmpC in Escherichia coli.
- In vivo phosphorylation of OmpR, the transcription activator of the ompF and ompC genes in Escherichia coli.