This Article Full Text 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 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 Wang, Y. Articles by Salyers, A. A. Search for Related Content PubMed PubMed Citation Articles by Wang, Y. Articles by Salyers, A. A.

Translational Control of Tetracycline Resistance and Conjugation in the Bacteroides Conjugative Transposon CTnDOT

New York University School of Medicine, Skirball Institute of Biomolecular Medicine, New York, New York,¹ Department of Microbiology, University of Illinois, Urbana, Illinois²

Received 11 August 2004/ Accepted 7 January 2005

The tetQ-rteA-rteB operon of the Bacteroides conjugative transposon CTnDOT is responsible for tetracycline control of the excision and transfer of CTnDOT. Previous studies revealed that tetracycline control of this operon occurred at the translational level and involved a hairpin structure located within the 130-base leader sequence that lies between the promoter of tetQ and the start codon of the gene. This hairpin structure is formed by two sequences, designated Hp1 and Hp8. Hp8 contains the ribosome binding site for tetQ. Examination of the leader region sequence revealed three sequences that might encode a leader peptide. One was only 3 amino acids long. The other two were 16 amino acids long. By introducing stop codons into the peptide coding regions, we have now shown that the 3-amino-acid peptide is the one that is essential for tetracycline control. Between Hp1 and Hp8 lies an 85-bp region that contains other possible RNA hairpin structures. Deletion analysis of this intervening DNA segment has now identified a sequence, designated Hp2, which is essential for tetracycline regulation. This sequence could form a short hairpin structure with Hp1. Mutations that made the Hp1-Hp2 structure more stable caused nearly constitutively high expression of the operon. Thus, stalling of ribosomes on the 3-amino-acid leader peptide could favor formation of the Hp1-Hp2 structure and thus preclude formation of the Hp1-Hp8 structure, releasing the ribosome binding site of tetQ. Finally, comparison of the CTnDOT tetQ leader regions with upstream regions of five tetQ genes found in other elements reveals that the sequences are virtually identical, suggesting that translational attenuation is responsible for control of tetracycline resistance in these other cases as well.

This article has been cited by other articles:

• Wardle, S. J., O'Carroll, M., Derbyshire, K. M., Haniford, D. B. (2005). The global regulator H-NS acts directly on the transpososome to promote Tn10 transposition. Genes Dev. 19: 2224-2235 [Abstract] [Full Text]