This Article Full Text (PDF) Other Versions of this Article: JB.01064-06v1 189/3/1072    most recent 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 Wesslund, N. A. Articles by Salyers, A. A. Search for Related Content PubMed PubMed Citation Articles by Wesslund, N. A. Articles by Salyers, A. A.

 Previous Article  |  Next Article 

J. Bacteriol. doi:10.1128/JB.01064-06
Copyright (c) 2006, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Integration and excision of the newly discovered Bacteroides conjugative transposon, CTnBST

Department of Microbiology, University of Illinois, Urbana, IL 61801

^* To whom correspondence should be addressed. Email: nadjasho{at}life.uiuc.edu,

	Abstract

Conjugative transposons (CTns) are major contributors to the spread of antibiotic resistance genes among Bacteroides species. CTnBST, a newly discovered Bacteroides conjugative transposon, carries an erythromycin resistance gene ermB and has previously been estimated to be about 100 kbp in size. We report here the location and sequencing of both of its ends. We have also located and sequenced the gene that catalyzes integration of CTnBST, intBST. The integrase gene encodes a 377 amino acid protein that has the C-terminal R K H R H Y motif that is characteristic of members of the tyrosine recombinase family of integrases. DNA sequence comparisons of the ends of CTnBST, the joined ends of the circular intermediate and the preferred site into which the circular form of CTnBST had integrated revealed that the preferred integration site (attB1) contained an 18 bp sequence of identity to the crossover region, attBST, on CTnBST. Although this site was used in about one half of the integration events, sequence analysis of integration events revealed that both CTnBST and a miniature form of CTnBST (miniBST) integrated into a variety of other sites in the chromosome. All of the sites had two conserved regions, AATCTG and AAAT. These two regions flanked a 2 bp sequence, bp10 and bp11 of the 18 bp sequence, that were variable in some of the different sites and sometimes in the attBST sequences. Our results suggest that CTnBST integrates site-selectively and that the crossover appears to occur within a 12 bp region that contains the two regions of conserved sequences.

This article has been cited by other articles:

• Song, B., Shoemaker, N. B., Gardner, J. F., Salyers, A. A. (2007). Integration Site Selection by the Bacteroides Conjugative Transposon CTnBST. J. Bacteriol. 189: 6594-6601 [Abstract] [Full Text]  
• Schlesinger, D. J., Shoemaker, N. B., Salyers, A. A. (2007). Possible Origins of CTnBST, a Conjugative Transposon Found Recently in a Human Colonic Bacteroides Strain. Appl. Environ. Microbiol. 73: 4226-4233 [Abstract] [Full Text]