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 Pomposiello, P. J.
Right arrow Articles by Bender, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pomposiello, P. J.
Right arrow Articles by Bender, R. A.

 Previous Article  |  Next Article 

J Bacteriol, February 1998, p. 578-585, Vol. 180, No. 3
0021-9193/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Two Roles for the DNA Recognition Site of the Klebsiella aerogenes Nitrogen Assimilation Control Protein

Pablo J. Pomposiello,dagger Brian K. Janes, and Robert A. Bender*

Department of Biology, The University of Michigan, Ann Arbor, Michigan 48109-1048

Received 11 July 1997/Accepted 4 November 1997

The nitrogen assimilation control protein (NAC) binds to a site within the promoter region of the histidine utilization operon (hutUH) of Klebsiella aerogenes, and NAC bound at this site activates transcription of hutUH. This NAC-binding site was characterized by a combination of random and directed DNA mutagenesis. Mutations that abolished or diminished in vivo transcriptional activation by NAC were found to lie within a 15-bp region contained within the 26-bp region protected by NAC from DNase I digestion. This 15-bp core has the palindromic ends ATA and TAT, and it matches the consensus for LysR family transcriptional regulators. Protein-binding experiments showed that transcriptional activation in vivo decreased with decreasing binding in vitro. In contrast to the NAC-binding site from hutUH, the NAC-binding site from the gdhA promoter failed to activate transcription from a semisynthetic promoter, and this failure was not due to weak binding or greatly distorted protein-DNA structure. Mutations in the promoter-proximal half-site of the NAC-binding site from gdhA allowed this site to activate transcription. Similar studies using the NAC-binding site from hut showed that two mutations in the promoter proximal half-site increased binding but abolished transcriptional activation. Interestingly, for symmetric mutations in the promoter-distal half-site, loss of transcriptional activation was always correlated with a decrease in binding. We conclude from these observations that if the binding in vitro reflects the binding in vivo, then binding of NAC to DNA is not sufficient for transcriptional activation and that the NAC-binding site can be functionally divided in two half-sites, with related but different functions.

* Corresponding author. Mailing address: Department of Biology, The University of Michigan, Ann Arbor, MI 48109-1048. Phone: (313) 936-2530. Fax: (313) 647-0884. E-mail: rbender{at}umich.edu.

dagger Present address: Department of Cellular & Molecular Toxicology, Harvard School of Public Health, Boston, MA 02115-6021.




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 © 1998 by the American Society for Microbiology. All rights reserved.