Unusual location of two nearby pairs of upstream activating sequences for HbpR, the main regulatory protein for the 2-hydroxybiphenyl degradation pathway of "Pseudomonas azelaica" HBP1.

Détails

ID Serval
serval:BIB_9F2185224841
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Unusual location of two nearby pairs of upstream activating sequences for HbpR, the main regulatory protein for the 2-hydroxybiphenyl degradation pathway of "Pseudomonas azelaica" HBP1.
Périodique
Microbiology
Auteur(s)
Jaspers M.C., Sturme M., van der Meer J.R.
ISSN
1350-0872 (Print)
ISSN-L
1350-0872
Statut éditorial
Publié
Date de publication
2001
Peer-reviewed
Oui
Volume
147
Numéro
Pt 8
Pages
2183-2194
Langue
anglais
Résumé
"Pseudomonas azelaica" HBP1 degrades 2-hydroxybiphenyl (2-HBP) and 2,2'-diHBP by employing a meta-cleavage pathway encoded by the hbpCAD genes. The regulatory gene hbpR, located directly upstream of the hbpCAD genes and oriented in the opposite direction, encodes a transcription activator protein belonging to the so-called XylR/DmpR subclass within the NtrC family. HbpR activates transcription from two separate sigma(54)-dependent promoters upstream of the hbpC and the hbpD genes, in the presence of the pathway substrates 2-HBP and 2,2'-diHBP. The DNA region upstream of the hbpC gene displays an unusual organization, containing two adjacent 0.3 kb regions that share 71% sequence identity. The DNA region most proximal to the hbpC promoter harbours one pair of putative upstream activating sequences (UASs C-1/C-2) and a small cryptic ORF that shows homology to hbpR itself. The second, more distal, region contains a second pair of putative UASs (UASs C-3/4) and the 5'-part of the hbpR gene. Transcriptional fusions in Escherichia coli between different deletions of the hbpR-hbpC intergenic region and the genes for bacterial luciferase revealed that most if not all of the transcriptional output from the hbpC promoter is mediated from the proximal UASs C-1/C-2. However, when the UASs C-1/C-2 were deleted and UASs C-3/C-4 were placed in an appropriate position with respect to the promoter region, the hbpC promoter was still inducible with 2-HBP, albeit at a lower level. Transcription studies in E. coli and "P. azelaica" revealed that the divergently oriented hbpR gene is expressed constitutively from a sigma(70)-dependent promoter situated within the cryptic ORF. The presence of UAS pair C-3/C-4 mediated a slightly higher promoter activity for transcription of hbpR.
Mots-clé
Bacterial Proteins/genetics, Bacterial Proteins/metabolism, Base Sequence, Biodegradation, Environmental, Biphenyl Compounds/metabolism, DNA, Intergenic, DNA-Binding Proteins/chemistry, DNA-Binding Proteins/genetics, Gene Expression Regulation, Bacterial, Genes, Regulator, Molecular Sequence Data, Operator Regions, Genetic, Promoter Regions, Genetic, Pseudomonas/genetics, Pseudomonas/growth & development, Trans-Activators, Transcription Factors/chemistry, Transcription Factors/genetics, Transcriptional Activation
Pubmed
Web of science
Création de la notice
21/01/2008 14:36
Dernière modification de la notice
03/03/2018 20:02
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