Integration host factor suppresses promiscuous activation of the sigma 54-dependent promoter Pu of Pseudomonas putida.
AUTOR(ES)
Pérez-Martín, J
RESUMO
In the presence of m-xylene, the Pu promoter of the TOL plasmid of Pseudomonas putida is activated by the prokaryotic enhancer-binding protein XylR. The intervening DNA segment between the upstream activating sequences (UASs) and those for RNA polymerase binding contains an integration host factor (IHF) attachment site that is required for full transcriptional activity. In the absence of IHF, the Pu promoter can be cross-activated by other members of the sigma 54-dependent family of regulatory proteins. Such illegitimate activation does not require the binding of the heterologous regulators to DNA and it is suppressed by bent DNA structures, either static or protein induced, between the promoter core elements (UAS and RNA polymerase recognition sequence). The role of IHF in some sigma 54 promoters is, therefore, not only a structural aid for assembling a correct promoter geometry but also that of an active suppressor (restrictor) of promiscuous activation by heterologous regulators for increased promoter specificity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=41322Documentos Relacionados
- Sigma 54 Levels and Physiological Control of the Pseudomonas putida Pu Promoter
- The sigma 54-dependent promoter Ps of the TOL plasmid of Pseudomonas putida requires HU for transcriptional activation in vivo by XylR.
- An upstream XylR- and IHF-induced nucleoprotein complex regulates the sigma 54-dependent Pu promoter of TOL plasmid.
- Coactivation in vitro of the sigma54-dependent promoter Pu of the TOL plasmid of Pseudomonas putida by HU and the mammalian HMG-1 protein.
- Alterations within the activation domain of the sigma 54-dependent activator DctD that prevent transcriptional activation.