This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sabaty, M. Articles by Kaplan, S. Search for Related Content PubMed PubMed Citation Articles by Sabaty, M. Articles by Kaplan, S.

 Previous Article  |  Next Article 

J. Bacteriol., 01 1996, 35-45, Vol 178, No. 1
Copyright © 1996, American Society for Microbiology

mgpS, a complex regulatory locus involved in the transcriptional control of the puc and puf operons in Rhodobacter sphaeroides 2.4.1

M Sabaty and S Kaplan
Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston 77225, USA.

A new method has been developed in order to select mutants showing decreased puc operon transcription in Rhodobacter sphaeroides 2.4.1. A transcriptional fusion of a promoterless fragment derived from the sacB gene, encoding the levansucrase from Bacillus subtilis, to the upstream regulatory region of the puc operon has been constructed. With appropriate levels of exogenous sucrose, survivors of a sucrose killing challenge have been isolated. Subsequent analysis revealed the presence of both cis- and trans-acting "down" mutations in relation to puc operon expression. One of the trans-acting regulatory mutations was chosen for further study. The original mutation showed less than 2% of the level of puc operon transcription compared with the wild type under aerobic conditions and an 86% reduction under dark dimethyl sulfoxide conditions. This mutation can be complemented by a 3.9-kb BamHI DNA fragment derived from a cosmid contained within a genomic cosmid bank. DNA sequence analysis of this fragment revealed the presence of a 2.8- kb open reading frame, designated mgpS, which would encode a 930-amino- acid protein. The N-terminal portion of the putative protein product presents homologies to proteins of the RNA helicase family. Disruption of the chromosomal mgpS resulted in decreased transcription of both puc and puf, while the presence of mgpS in multicopy in the wild type, 2.4.1., increased puc expression by a factor of 2 under aerobic conditions. Structural analysis of the mgpS locus revealed that expression of mgpS was likely to be complex. A smaller protein containing the 472 C-terminal amino acids of MgpS is able to act by itself as an activator of puc transcription and is expressed independently of the large open reading frame in which it is contained.

This article has been cited by other articles:

• Roh, J. H., Smith, W. E., Kaplan, S. (2004). Effects of Oxygen and Light Intensity on Transcriptome Expression in Rhodobacter sphaeroides 2.4.1: REDOX ACTIVE GENE EXPRESSION PROFILE. J. Biol. Chem. 279: 9146-9155 [Abstract] [Full Text]  
• Oh, J.-I., Ko, I.-J., Kaplan, S. (2003). Digging deeper: uncovering genetic loci which modulate photosynthesis gene expression in Rhodobacter sphaeroides 2.4.1. Microbiology 149: 949-960 [Abstract] [Full Text]  
• Sabaty, M., Avazeri, C., Pignol, D., Vermeglio, A. (2001). Characterization of the Reduction of Selenate and Tellurite by Nitrate Reductases. Appl. Environ. Microbiol. 67: 5122-5126 [Abstract] [Full Text]  
• Triccas, J. A., Berthet, F.-X., Pelicic, V., Gicquel, B. (1999). Use of fluorescence induction and sucrose counterselection to identify Mycobacterium tuberculosis genes expressed within host cells. Microbiology 145: 2923-2930 [Abstract] [Full Text]  
• Pasternak, C., Haberzettl, K., Klug, G. (1999). Thioredoxin Is Involved in Oxygen-Regulated Formation of the Photosynthetic Apparatus of Rhodobacter sphaeroides. J. Bacteriol. 181: 100-106 [Abstract] [Full Text]  
• Reyrat, J.-M., Pelicic, V., Gicquel, B., Rappuoli, R. (1998). Counterselectable Markers: Untapped Tools for Bacterial Genetics and Pathogenesis. Infect. Immun. 66: 4011-4017 [Full Text]  
• Zeilstra-Ryalls, J., Gomelsky, M., Eraso, J. M., Yeliseev, A., O'Gara, J., Kaplan, S. (1998). Control of Photosystem Formation in Rhodobacter sphaeroides. J. Bacteriol. 180: 2801-2809 [Full Text]  
• Zeilstra-Ryalls, J. H., Kaplan, S. (1998). Role of the fnrL Gene in Photosystem Gene Expression and Photosynthetic Growth of Rhodobacter sphaeroides 2.4.1. J. Bacteriol. 180: 1496-1503 [Abstract] [Full Text]