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 Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Reitzer, L J Articles by Magasanik, B Search for Related Content PubMed PubMed Citation Articles by Reitzer, L J Articles by Magasanik, B

research-article

Activation of glnA transcription by nitrogen regulator I (NRI)-phosphate in Escherichia coli: evidence for a long-range physical interaction between NRI-phosphate and RNA polymerase.

Department of Molecular and Cell Biology, University of Texas, Dallas,Richardson 75083-0688.

ABSTRACT

Growth of cells of Escherichia coli in nitrogen-limited medium induces the formation of glutamine synthetase, product of the glnA gene, and of other proteins that facilitate the assimilation of nitrogen-containing compounds. Transcription from the glnAp2 promoter of the glnALG operon requires the phosphorylation of nitrogen regulator I (NRI) and, for optimal transcription, the binding of NRI-phosphate to two sites that can be over 1,000 base pairs from the binding site for RNA polymerase. In other procaryotic genes, placement of an activator-binding site further upstream from the start site of transcription diminishes expression. To determine how NRI-phosphate activates transcription and why NRI-dependent transcription differs from activation in other systems, we constructed recombinant plasmids with small alterations between the binding sites for NRI-phosphate and RNA polymerase and between the two high-affinity NRI-binding sites. We demonstrate that tightly bound NRI-phosphate activated transcription from either side of the DNA helix when at least 30 base pairs separated NRI-phosphate from RNA polymerase. In contrast, activation from a partial NRI-binding site was effective only from one side of the DNA. We also observed that glnA expression was optimal when the two high-affinity NRI-binding sites were on the same side of the DNA helix. We explain these results on the basis of a hypothesis that a contact between RNA polymerase and NRI-phosphate bound to an upstream site determines the rate of glnA transcription.

This article has been cited by other articles:

• Gronewold, T. M. A., Kaiser, D. (2007). Mutations of the Act Promoter in Myxococcus xanthus. J. Bacteriol. 189: 1836-1844 [Abstract] [Full Text]  
• Harrod, A. C., Yang, X., Junker, M., Reitzer, L. (2004). Evidence for a Second Interaction between the Regulatory Amino-terminal and Central Output Domains of the Response Regulator NtrC (Nitrogen Regulator I) in Escherichia coli. J. Biol. Chem. 279: 2350-2359 [Abstract] [Full Text]  
• Jyot, J., Dasgupta, N., Ramphal, R. (2002). FleQ, the Major Flagellar Gene Regulator in Pseudomonas aeruginosa, Binds to Enhancer Sites Located Either Upstream or Atypically Downstream of the RpoN Binding Site. J. Bacteriol. 184: 5251-5260 [Abstract] [Full Text]  
• Belitsky, B. R., Sonenshein, A. L. (1999). An enhancer element located downstream of the major glutamate dehydrogenase gene of Bacillus subtilis. Proc. Natl. Acad. Sci. USA 96: 10290-10295 [Abstract] [Full Text]  
• Peñaloza-Vázquez, A., Bender, C. L. (1998). Characterization of CorR, a Transcriptional Activator Which Is Required for Biosynthesis of the Phytotoxin Coronatine. J. Bacteriol. 180: 6252-6259 [Abstract] [Full Text]  
• Wang, J. T., Gralla, J. D. (1996). The Transcription Initiation Pathway of Sigma 54Mutants That Bypass the Enhancer Protein Requirement. IMPLICATIONS FOR THE MECHANISM OF ACTIVATION. J. Biol. Chem. 271: 32707-32713 [Abstract] [Full Text]  
• Cullen, P. J., Bowman, W. C., Kranz, R. G. (1996). In Vitro Reconstitution and Characterization of the Rhodobacter capsulatus NtrB and NtrC Two-component System. J. Biol. Chem. 271: 6530-6536 [Abstract] [Full Text]  
• Porter, S C, North, A K, Wedel, A B, Kustu, S (1993). Oligomerization of NTRC at the glnA enhancer is required for transcriptional activation.. Genes Dev. 7: 2258-2273 [Abstract]  
• Wedel, A, Weiss, D., Popham, D, Droge, P, Kustu, S (1990). A bacterial enhancer functions to tether a transcriptional activator near a promoter. Science 248: 486-490 [Abstract]