JB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Sze, C. C.
Right arrow Articles by Shingler, V.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Sze, C. C.
Right arrow Articles by Shingler, V.

Journal of Bacteriology, May 2001, p. 2842-2851, Vol. 183, No. 9
0021-9193/01/$04.00+0   DOI: 10.1128/JB.183.9.2842-2851.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.

In Vivo and In Vitro Effects of Integration Host Factor at the DmpR-Regulated sigma 54-Dependent Po Promoter

Chun Chau Sze, Andrew D. Laurie, and Victoria Shingler*

Department of Cell and Molecular Biology, Umeå University, S-901 87 Umeå, Sweden

Received 23 October 2000/Accepted 20 February 2001

Transcription from the Pseudomonas CF600-derived sigma 54-dependent promoter Po is controlled by the aromatic-responsive activator DmpR. Here we examine the mechanism(s) by which integration host factor (IHF) stimulates DmpR-activated transcriptional output of the Po promoter both in vivo and in vitro. In vivo, the Po promoter exhibits characteristics that typify many sigma 54-dependent promoters, namely, a phasing-dependent tolerance with respect to the distance from the regulator binding sites to the distally located RNA polymerase binding site, and a strong dependence on IHF for optimal promoter output. IHF is shown to affect transcription via structural repercussions mediated through binding to a single DNA signature located between the regulator and RNA polymerase binding sites. In vitro, using DNA templates that lack the regulator binding sites and thus bypass a role of IHF in facilitating physical interaction between the regulator and the transcriptional apparatus, IHF still mediates a DNA binding-dependent stimulation of Po transcription. This stimulatory effect is shown to be independent of previously described mechanisms for the effects of IHF at sigma 54 promoters such as aiding binding of the regulator or recruitment of sigma 54-RNA polymerase via UP element-like DNA. The effect of IHF could be traced to promotion and/or stabilization of open complexes within the nucleoprotein complex that may involve an A+T-rich region of the IHF binding site and promoter-upstream DNA. Mechanistic implications are discussed in the context of a model in which IHF binding results in transduction of DNA instability from an A+T-rich region to the melt region of the promoter.

* Corresponding author. Mailing address: Department of Cell and Molecular Biology, Umeå University, S-901 87 Umeå, Sweden. Phone: 46 90 7852534. Fax: 46 90 771420. E-mail: victoria.shingler{at}cmb.umu.se.

Journal of Bacteriology, May 2001, p. 2842-2851, Vol. 183, No. 9
0021-9193/01/$04.00+0   DOI: 10.1128/JB.183.9.2842-2851.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 2001 by the American Society for Microbiology. All rights reserved.