In vitro functional characterization of overproduced Escherichia coli katF/rpoS gene product.
The katF/rpoS gene product (sigma s), a central regulator of stationary-phase gene expression in Escherichia coli, has been purified from an overproducing strain. sigma s was used as an immunogen for the production of monoclonal antibodies. Previous sequence analysis of sigma s strongly indicated homology to the sigma factor family. We show biochemically in this paper that sigma s is a sigma factor. This protein can bind to core RNA polymerase (E), and this binding can be competed effectively by the major E. coli transcription initiation factor, sigma 70. Immunopurified sigma s holoenzyme (E sigma s) transcribes the promoters of the bolAp1 gene and the xthA gene. Interestingly, both promoters can also be transcribed by sigma 70 holoenzyme (E sigma 70).
Nguyen
L H
LH
McArdle Laboratory for Cancer Research, University of Wisconsin-Madison 53706.
Jensen
D B
DB
Thompson
N E
NE
Gentry
D R
DR
Burgess
R R
RR
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D012321:DNA-Directed RNA Polymerases