Abstract
Pheromone-inducible conjugation in the Enterococcus faecalis pCF10 system is regulated by the PrgX transcription factor through binding interactions at two operator binding sites (XBS1 and XBS2) upstream of the transcription start site of the prgQ operon encoding the conjugation machinery. Repression of transcription requires the interaction of a PrgX tetramer with both XBSs via formation of a DNA loop. The ability of PrgX to regulate prgQ transcription is modulated by its interaction with two antagonistic regulatory peptides, ICF10 (I) and cCF10 (C); the former peptide inhibits prgQ transcription, while the latter peptide enhances prgQ transcription. In this report, we used electrophoretic mobility shift assays (EMSAs) and DNase footprinting to examine binding interactions between the XBS operator sites and various forms of PrgX (Apo-X, PrgX/I, and PrgX/C). Whereas a previous model based on high-resolution structures of PrgX proposed that the functional differences between PrgX/C and PrgX/I resulted from differences in PrgX oligomerization state, the current results show that specific differences in XBS2 occupancy by bound tetramers account for the differential regulatory properties of the two peptide/PrgX complexes and for the effects of XBS mutations on regulation. The results also confirmed a DNA looping model of PrgX function.
Original language | English (US) |
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Journal | Journal of bacteriology |
Volume | 204 |
Issue number | 12 |
DOIs | |
State | Published - Dec 2022 |
Bibliographical note
Funding Information:We thank Yuqing Chen for assistance with protein and reagent preparation. This research was supported by USPHS grant 5R35GM118079 to G.M.D. T.S. was a recipient of a fellowship from the Uehara Memorial Foundation.
Publisher Copyright:
Copyright © 2022 American Society for Microbiology. All Rights Reserved.
Keywords
- antibiotic resistance
- cell-cell signaling
- gene transfer
- sex pheromone
PubMed: MeSH publication types
- Journal Article
- Research Support, N.I.H., Extramural
- Research Support, Non-U.S. Gov't