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 Krüger, R.
Right arrow Articles by Filutowicz, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Krüger, R.
Right arrow Articles by Filutowicz, M.

 Previous Article  |  Next Article 

Journal of Bacteriology, May 2000, p. 2461-2467, Vol. 182, No. 9
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

Dimers of pi  Protein Bind the A+T-Rich Region of the R6K gamma  Origin near the Leading-Strand Synthesis Start Sites: Regulatory Implications

Ricardo Krüger and Marcin Filutowicz*

Department of Bacteriology, University of Wisconsin---Madison, Madison, Wisconsin 53706

Received 4 November 1999/Accepted 9 February 2000

The replication of gamma  origin, a minimal replicon derived from plasmid R6K, is controlled by the Rep protein pi . At low intracellular concentrations, pi  activates the gamma  origin, while it inhibits replication at elevated concentrations. Additionally, pi  acts as a transcription factor (auto)repressing its own synthesis. These varied regulatory functions depend on pi  binding to reiterated DNA sequences bearing a TGAGNG motif. However, pi  also binds to a "non-iteron" site (i.e., not TGAGNG) that resides in the A+T-rich region adjacent to the iterons. This positioning places the non-iteron site near the start sites for leading-strand synthesis that also occur in the A+T-rich region of gamma  origin. We have hypothesized that origin activation (at low pi  levels) would require the binding of pi  monomers to iterons, while the binding of pi  dimers to the non-iteron site (at high pi  levels) would be required to inhibit priming. Although monomers as well as dimers can bind to an iteron, we demonstrate that only dimers bind to the non-iteron site. Two additional pieces of data support the hypothesis of negative replication control by pi  binding to the non-iteron site. First, pi  binds to the non-iteron site about eight times less well than it binds to a single iteron. Second, hyperactive variants of pi  protein (called copy-up) either do not bind to the non-iteron site or bind to it less well than wild-type pi . We propose a replication control mechanism whereby pi  would directly inhibit primer formation.

* Corresponding author. Mailing address: Department of Bacteriology, E. B. Fred Hall, University of Wisconsin---Madison, 1550 Linden Dr., Madison, WI 53706. Phone: (608) 262-6947. Fax: (608) 262-9865. E-mail: msfiluto{at}facstaff.wisc.edu.

Journal of Bacteriology, May 2000, p. 2461-2467, Vol. 182, No. 9
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:

  • Kunnimalaiyaan, S., Rakowski, S. A., Filutowicz, M. (2007). Structure-Based Functional Analysis of the Replication Protein of Plasmid R6K: Key Amino Acids at the {pi}/DNA Interface. J. Bacteriol. 189: 4953-4956 [Abstract] [Full Text]  
  • Kunnimalaiyaan, S., Kruger, R., Ross, W., Rakowski, S. A., Filutowicz, M. (2004). Binding Modes of the Initiator and Inhibitor Forms of the Replication Protein {pi} to the {gamma} ori Iteron of Plasmid R6K. J. Biol. Chem. 279: 41058-41066 [Abstract] [Full Text]  
  • Napierala, M., Dere, R., Vetcher, A., Wells, R. D. (2004). Structure-dependent Recombination Hot Spot Activity of GAA{middle dot}TTC Sequences from Intron 1 of the Friedreich's Ataxia Gene. J. Biol. Chem. 279: 6444-6454 [Abstract] [Full Text]  
  • Pluciennik, A., Iyer, R. R., Napierala, M., Larson, J. E., Filutowicz, M., Wells, R. D. (2002). Long CTG{middle dot}CAG Repeats from Myotonic Dystrophy Are Preferred Sites for Intermolecular Recombination. J. Biol. Chem. 277: 34074-34086 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»