Genetic analysis of plasmid-specific pheromone signaling encoded by pPD1 in Enterococcus faecalis.

Certain plasmids in Enterococcus faecalis encode a mating response to recipient-produced peptide sex pheromones. Targeted disruption of tra genes on pPD1 suggested that TraA plays a central role in the plasmid-specific pheromone signaling pathway. TraA functioned as a negative regulator for the pheromone-inducible conjugal transfer. Complementation analysis of pPD1 tra gene mutants by pAD1 suggested that the pheromone binding function of TraC was non-specific between these plasmids, but the function of TraA and the pheromone shutdown function of TraB are plasmid-specific.