FinP of Plasmid R1

Plasmid R1 belongs to the so called F-like plasmids, relatives of the prototypic fertility factor, F. It is, in the wild-type form, repressed, i.e. only one out of ca. 1000 plasmid-carrying cells is able to participate in conjugation. We established that one of the small RNA species encoded by plasmid R1is an antisense RNA, called FinP ( fin: fertility inhibition), which, in conjunction with the protein FinO, constitutes a repressor for conjugative DNA transfer. We have performed extensive mutational analyses of the FinP RNA and showed that it consists of two stem-loop structures which interact with the target traJ mRNA and prevent its expression. Gene traJ encodes a positive regulator of the tra-operon and, thus, lack of protein TraJ results in shut off of tra-operon expression at the promoter preceding gene traY.

Publication

Koraimann, G., Koraimann, C., Koronakis, V., Schlager, S., and G. Högenauer (1991) Repression and derepression of conjugation of plasmid R1 by wild-type and mutated finP antisense RNA. Mol. Microbiol. 5: 77-87. Here is the Abstract