Identification of the rctA gene, which is required for repression of conjugative transfer of rhizobial symbiotic megaplasmids.

ABSTRACT: An analysis of the conjugative transfer of pRetCFN42d, the symbiotic plasmid (pSym) of Rhizobium etli, has revealed a novel gene, rctA, as an essential element of a regulatory system for silencing the conjugative transfer of R. etli pSym by repressing the transcription of conjugal transfer genes in standard laboratory media. The rctA gene product lacks sequence conservation with other proteins of known function but may belong to the winged-helix DNA-binding subfamily of transcriptional regulators. Similar to that of many transcriptional repressors, rctA transcription seems to be positively autoregulated. rctA expression is greatly reduced upon overexpression of another gene, rctB, previously identified as a putative activator of R. etli pSym conjugal transfer. Thus, rctB seems to counterac

SUBMITTER: Perez-Mendoza D 

PROVIDER: S-EPMC1272987 | biostudies-literature | 2005 Nov

REPOSITORIES: biostudies-literature