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 Notley-McRobb, L.
Right arrow Articles by Ferenci, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Notley-McRobb, L.
Right arrow Articles by Ferenci, T.

 Previous Article  |  Next Article 

Journal of Bacteriology, February 2002, p. 739-745, Vol. 184, No. 3
0021-9193/01/$04.00+0     DOI: 10.1128/JB.184.3.739-745.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Regulation of mutY and Nature of Mutator Mutations in Escherichia coli Populations under Nutrient Limitation

Lucinda Notley-McRobb, Rachel Pinto, Shona Seeto, and Thomas Ferenci*

Department of Microbiology G08, University of Sydney, New South Wales 2006, Australia

Received 21 June 2001/ Accepted 17 August 2001

Previous analysis of aerobic, glucose-limited continuous cultures of Escherichia coli revealed that G:C-to-T:A (G:C->T:A) transversions were the most commonly occurring type of spontaneous mutation. One possible explanation for the preponderance of these mutations was that nutrient limitation repressed MutY-dependent DNA repair, resulting in increased proportions of G:C->T:A transversions. The regulation of the mutY-dependent DNA repair system was therefore studied with a transcriptional mutY-lacZ fusion recombined into the chromosome. Expression from the mutY promoter was fourfold higher under aerobic conditions than under anaerobic conditions. But mutY expression was higher in glucose- or ammonia-limited chemostats than in nutrient-excess batch culture, so mutY was not downregulated by nutrient limitation. An alternative explanation for the frequency of G:C->T:A transversions was the common appearance of mutY mutator mutations in the chemostat populations. Of 11 chemostat populations screened in detail, six contained mutators, and the mutator mutation in four cultures was located in the region of mutY at 66 min on the chromosome. The spectrum of mutations and rate of mutation in these isolates were fully consistent with a mutY-deficiency in each strain. Based on PCR analysis of the region within and around mutY, isolates from three individual populations contained deletions extending at least 2 kb upstream of mutY and more than 5 kb downstream. In the fourth population, the deletion was even longer, extending at least 5 kb upstream and 5 kb downstream of mutY. The isolation of mutY mutator strains from four independent populations with extensive chromosomal rearrangements suggests that mutY inactivation by deletion is a means of increasing mutation rates under nutrient limitation and explains the observed frequency of G:C->T:A mutations in glucose-limited chemostats.

* Corresponding author. Mailing address: Department of Microbiology G08, University of Sydney, New South Wales 2006, Australia. Phone: (61-2)-9351-4277. Fax: (61-2)-9351-4571. E-mail: tferenci{at}mail.usyd.edu.au.

Journal of Bacteriology, February 2002, p. 739-745, Vol. 184, No. 3
0021-9193/01/$04.00+0     DOI: 10.1128/JB.184.3.739-745.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Huang, S., Kang, J., Blaser, M. J. (2006). Antimutator Role of the DNA Glycosylase mutY Gene in Helicobacter pylori.. J. Bacteriol. 188: 6224-6234 [Abstract] [Full Text]  
  • Hall, L. M. C., Henderson-Begg, S. K. (2006). Hypermutable bacteria isolated from humans - a critical analysis.. Microbiology 152: 2505-2514 [Abstract] [Full Text]  
  • de Weert, S., Dekkers, L. C., Kuiper, I., Bloemberg, G. V., Lugtenberg, B. J. J. (2004). Generation of Enhanced Competitive Root-Tip-Colonizing Pseudomonas Bacteria through Accelerated Evolution. J. Bacteriol. 186: 3153-3159 [Abstract] [Full Text]  
  • Notley-McRobb, L., Seeto, S., Ferenci, T. (2002). Enrichment and Elimination of mutY Mutators in Escherichia coli Populations. Genetics 162: 1055-1062 [Abstract] [Full Text]  
  • Shaver, A. C., Dombrowski, P. G., Sweeney, J. Y., Treis, T., Zappala, R. M., Sniegowski, P. D. (2002). Fitness Evolution and the Rise of Mutator Alleles in Experimental Escherichia coli Populations. Genetics 162: 557-566 [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»