The FinOP repressor system of plasmid R1: analysis of the antisense RNA control of traJ expression and conjugative DNA transfer.

A key determinant of the frequency of IncF plasmid-mediated DNA transfer between enterobacterial cells is the FinOP system. traJ, a positive regulator of the transfer (tra) genes is controlled at the post-transcriptional level by two negative elements, finP and finO. FinP is a plasmid-specific antisense RNA, whereas finO encodes a proteic co-repressor which is not plasmid specific but exchangeable among F-like plasmids.