PMID:9335270
| Citation |
Bhagwat, SP, Rice, MR, Matthews, RG and Blumenthal, RM (1997) Use of an inducible regulatory protein to identify members of a regulon: application to the regulon controlled by the leucine-responsive regulatory protein (Lrp) in Escherichia coli. J. Bacteriol. 179:6254-63 |
|---|---|
| Abstract |
Procedures were developed to facilitate the identification of genes that belong to a given regulon and characterization of their responses to the regulator. The regulon controlled by the Escherichia coli leucine-responsive regulatory protein (Lrp) was studied by isolating random transcriptional fusions to lacZ, using lambda placMu53 and a strain in which lrp is under isopropylthio-beta-D-galactopyranoside (IPTG)-inducible control. Fusions exhibiting IPTG-responsive beta-galactosidase activity were cloned by integrating the suicide vector pIVET1 via homologous recombination at lacZ, followed by self-ligating digested chromosomal DNA. We verified the patterns of lacZ expression after using the plasmid clones to generate merodiploid strains with interrupted and uninterrupted copies of the same sequence. If the merodiploid expression pattern was unchanged from that shown by the original fusion strain, then the cloned fusion was responsible for the regulatory pattern of interest; a difference in the expression pattern could indicate that the original strain carried multiple fusions or that there were autogenous effects of having interrupted the fused gene. Using these procedures, we generated a fusion library of approximately 5 x 10(6) strains; approximately 3,000 of these strains were screened, yielding 84 Lrp-responsive fusions, and 10 of the 84 were phenotypically stable and were characterized. The responses of different fusions in a given operon to in vivo Lrp titrations revealed variations in expression with the position of insertion. Among the newly identified members of the regulon is an open reading frame (orf3) between rpiA and serA. Also, expression of a fusion just downstream of dinF was found to be Lrp dependent only in stationary phase. |
| Links | |
| Keywords |
Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Bacteriophage mu/genetics; Cloning, Molecular; DNA-Binding Proteins/genetics; DNA-Binding Proteins/metabolism; Escherichia coli/genetics; Escherichia coli/growth & development; Escherichia coli/metabolism; Escherichia coli Proteins; Gene Expression Regulation, Bacterial; Gene Library; Leucine/pharmacology; Leucine-Responsive Regulatory Protein; Membrane Transport Proteins; Open Reading Frames; Operon; Regulon; Sequence Analysis, DNA; Transcription Factors |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.