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 Weickert, M J Articles by Adhya, S Search for Related Content PubMed PubMed Citation Articles by Weickert, M J Articles by Adhya, S

 Previous Article  |  Next Article 

J Bacteriol. 1993 January; 175(1): 251-258

research-article

Control of transcription of gal repressor and isorepressor genes in Escherichia coli.

Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.

ABSTRACT

Two regulatory proteins, Gal repressor and isorepressor, control the expression of the gal and mgl operons in Escherichia coli. The transcription start sites for galR and galS, the genes for the repressor and isorepressor, were determined by primer extension of in vivo transcripts. Study of the promoter-lacZ gene fusions introduced into the chromosome indicated that galS expression was elevated in cells in which the normal galS gene was interrupted, but not in cells in which the galR gene was deleted. When both genes were disrupted, galS expression was further elevated. Expression from the galS promoter was stimulated by the addition of D-fucose, repressed by glucose, and dependent on cyclic AMP receptor protein (CRP). Expression of a similar gene fusion of the galR promoter to lacZ was unregulated. Both galR and galS genes contain two potential operator sites (OE and OI) and a CRP-binding site. The arrangement of OE, OI, and the CRP-binding site in the galS gene is analogous to the arrangement in the gal and mgl promoters, but the arrangement in galR is atypical. The increased concentration of the isorepressor when inducer is present may facilitate early shutoff of the isorepressor-regulated genes of the gal regulon when inducer (substrate) concentration falls.

This article has been cited by other articles:

• Zheng, D., Constantinidou, C., Hobman, J. L., Minchin, S. D. (2004). Identification of the CRP regulon using in vitro and in vivo transcriptional profiling. Nucleic Acids Res 32: 5874-5893 [Abstract] [Full Text]  
• Moller, T., Franch, T., Udesen, C., Gerdes, K., Valentin-Hansen, P. (2002). Spot 42 RNA mediates discoordinate expression of the E. coli galactose operon. Genes Dev. 16: 1696-1706 [Abstract] [Full Text]  
• Vaughan, E. E., van den Bogaard, P. T. C., Catzeddu, P., Kuipers, O. P., de Vos, W. M. (2001). Activation of Silent gal Genes in the lac-gal Regulon of Streptococcus thermophilus. J. Bacteriol. 183: 1184-1194 [Abstract] [Full Text]  
• Swanson, B. L., Hamood, A. N. (2000). Autoregulation of the Pseudomonas aeruginosa Protein PtxS Occurs through a Specific Operator Site within the ptxS Upstream Region. J. Bacteriol. 182: 4366-4371 [Abstract] [Full Text]  
• Swanson, B. L., Colmer, J. A., Hamood, A. N. (1999). The Pseudomonas aeruginosa Exotoxin A Regulatory Gene, ptxS: Evidence for Negative Autoregulation. J. Bacteriol. 181: 4890-4895 [Abstract] [Full Text]  
• Berlyn, M. K. B. (1998). Linkage Map of Escherichia coli K-12, Edition 10: The Traditional Map. Microbiol. Mol. Biol. Rev. 62: 814-984 [Abstract] [Full Text]  
• Nieto, C., Espinosa, M., Puyet, A. (1997). The Maltose/Maltodextrin Regulon of Streptococcus pneumoniae. DIFFERENTIAL PROMOTER REGULATION BY THE TRANSCRIPTIONAL REPRESSOR MalR. J. Biol. Chem. 272: 30860-30865 [Abstract] [Full Text]  
• Shin, D., Lim, S., Seok, Y.-J., Ryu, S. (2001). Heat Shock RNA Polymerase (Esigma 32) Is Involved in the Transcription of mlc and Crucial for Induction of the Mlc Regulon by Glucose in Escherichia coli. J. Biol. Chem. 276: 25871-25875 [Abstract] [Full Text]