Coactivation of the RpoS-Dependent proP P2 Promoter by Fis and Cyclic AMP Receptor Protein
AUTOR(ES)
McLeod, Sarah M.
FONTE
American Society for Microbiology
RESUMO
The Escherichia coli proP P2 promoter, which directs the expression of an integral membrane transporter of proline, glycine betaine, and other osmoprotecting compounds, is induced upon entry into stationary phase to protect cells from osmotic shock. Transcription from the P2 promoter is completely dependent on RpoS (ς38) and Fis. Fis activates transcription by binding to a site centered at −41, which overlaps the promoter, where it makes a specific contact with the C-terminal domain of the α subunit of RNA polymerase (α-CTD). We show here that Fis and cyclic AMP (cAMP) receptor protein (CRP)-cAMP collaborate to activate transcription synergistically in vitro. Coactivation both in vivo and in vitro is dependent on CRP binding to a site centered at −121.5, but CRP without Fis provides little activation. The contribution by CRP requires the correct helical phasing of the CRP site and a functional activation region 1 on CRP. We provide evidence that coactivation is achieved by Fis and CRP independently contacting each of the two α-CTDs. Efficient transcription in vitro requires that both activators must be preincubated with the DNA prior to addition of RNA polymerase.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=101903Documentos Relacionados
- Fis activates the RpoS-dependent stationary-phase expression of proP in Escherichia coli.
- Cyclic AMP receptor protein functions as a repressor of the osmotically inducible promoter proP P1 in Escherichia coli.
- Molecular characterization of the promoter of osmY, an rpoS-dependent gene.
- Analysis of Promoter Elements Involved in the Transcriptional Initiation of RpoS-Dependent Borrelia burgdorferi Genes
- Osmotic regulation of rpoS-dependent genes in Escherichia coli.