Structural analysis of the Anti-Q-Qs interaction: RNA-mediated regulation of E. faecalis plasmid pCF10 conjugation

Sonia Shokeen, Christopher M. Johnson, Tony J. Greenfield, Dawn A. Manias, Gary M. Dunny, Keith E. Weaver

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Conjugation of the E. faecalis plasmid pCF10 is triggered in response to peptide sex pheromone cCF10 produced by potential recipients. Regulation of this response is complex and multi-layered and includes a small regulatory RNA, Anti-Q that participates in a termination/antitermination decision controlling transcription of the conjugation structural genes. In this study, the secondary structure of the Anti-Q transcript and its sites of interaction with its target, Qs, were determined. The primary site of interaction occurred at a centrally-located loop whose sequence showed high variability in analogous molecules on other pheromone-responsive plasmids. This loop, designated the specificity loop, was demonstrated to be important but not sufficient for distinguishing between Qs molecules from pCF10 and another pheromone-responsive plasmid pAD1. A loop 5' from the specificity loop which carries a U-turn motif played no demonstrable role in Anti-Q-Qs interaction or regulation of the termination/antitermination decision. These results provide direct evidence for a critical role of Anti-Q-Qs interactions in posttranscriptional regulation of pCF10 transfer functions.

Original languageEnglish (US)
Pages (from-to)26-35
Number of pages10
JournalPlasmid
Volume64
Issue number1
DOIs
StatePublished - Jul 2010

Bibliographical note

Funding Information:
We acknowledge the technical assistance of Shirisha Reddy from our laboratory. This work was supported by Public Health Service grant GM55544 and the Division of Basic Biomedical Sciences, Sanford School of Medicine (Weaver) and GM49530 (Dunny).

Keywords

  • Antisense RNA
  • Conjugation
  • Plasmid
  • RNA structure
  • Transcription attenuation

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