Journal of Bacteriology, October 2001, p. 5974-5981, Vol. 183, No. 20
0021-9193/01/$04.00+0 DOI: 10.1128/JB.183.20.5974-5981.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544
Received 1 June 2001/Accepted 16 July 2001
The stationary-phase response exhibited by Escherichia
coli upon nutrient starvation is mainly induced by a decrease
of the ClpXP-dependent degradation of the alternate primary
factor RpoS. Although it is known that the specific regulation of this proteolysis is exercised by the orphan response regulator SprE, it
remains unclear how SprE's activity is regulated in vivo. Previous studies have demonstrated that the cellular content of SprE itself is
paradoxically increased in stationary-phase cells in an RpoS-dependent fashion. We show here that this RpoS-dependent upregulation of SprE
levels is due to increased transcription. Furthermore, we demonstrate
that sprE is part of the two-gene
rssA-sprE operon, but it can also be transcribed from an
additional RpoS-dependent promoter located in the
rssA-sprE intergenic region. In addition, by using an
in-frame deletion in rssA we found that RssA does not
regulate either SprE or RpoS under the conditions tested.
This article has been cited by other articles:
| Appl. Environ. Microbiol. | Infect. Immun. | Eukaryot. Cell |
|---|---|---|
| Mol. Cell. Biol. | J. Virol. | Microbiol. Mol. Biol. Rev. |
| ALL ASM JOURNALS |