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 Peralta-Gil, M.
Right arrow Articles by Espín, G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Peralta-Gil, M.
Right arrow Articles by Espín, G.

 Previous Article  |  Next Article 

Journal of Bacteriology, October 2002, p. 5672-5677, Vol. 184, No. 20
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.20.5672-5677.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Expression of the Azotobacter vinelandii Poly-ß-Hydroxybutyrate Biosynthetic phbBAC Operon Is Driven by Two Overlapping Promoters and Is Dependent on the Transcriptional Activator PhbR

Martín Peralta-Gil,1 Daniel Segura,1 Josefina Guzmán,1 Luis Servín-González,2 and Guadalupe Espín1*

Departamento de Microbiología Molecular, Instituto de Biotecnología,1 Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Cuernavaca Morelos 62250, Mexico2

Received 29 May 2002/ Accepted 7 July 2002

The Azotobacter vinelandii phbBAC genes encode the enzymes for poly-ß-hydroxybutyrate (PHB) synthesis. The phbR gene, which is located upstream of and in the opposite direction of phbBAC, encodes PhbR, a transcriptional activator which is a member of the AraC family of activators. Here we report that a mutation in phbR reduced PHB accumulation and transcription of a phbB-lacZ fusion. We also report that phbB is transcribed from two overlapping promoters, pB1 and pB2. The region corresponding to the -35 region of pB1 overlaps the pB2 -10 region. In the phbR mutant, expression of phbB from the pB1 promoter is significantly reduced, whereas expression from the pB2 promoter is slightly increased. Two phbR promoters, pR1 and pR2, were also identified. Transcription from pR2 was shown to be dependent on {sigma}S. Six conserved 18-bp sites, designated R1 to R6, are present within the phbR-phbB intergenic region and are proposed to be putative binding targets for PhbR. R1 overlaps the -35 region of the pB1 promoter. A model for the regulation of phbB transcription by PhbR is proposed.

* Corresponding author. Mailing address: Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo Postal 510-3, Cuernavaca Morelos 62250, Mexico. Phone: 52-73-291644. Fax: 52-73-172388. E-mail: espin{at}ibt.unam.mx.

Journal of Bacteriology, October 2002, p. 5672-5677, Vol. 184, No. 20
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.20.5672-5677.2002
Copyright © 2002, 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 © 2002 by the American Society for Microbiology. All rights reserved.