Control of conjugation in the plasmid pSf-R27

Abstract

IncHI plasmids are prevalent amongst the Enterobacteriaceae and can confer a multi-drug resistance phenotype upon the host. IncHI plasmids are also thermosensitive for conjugative transfer. Conjugation can occur optimally at 22°C to 30°C, but it is repressed at 37°C. pSf-R27 is a large and self-transmissible IncHI 1 plasmid. It encodes homologues to the transcriptional regulators H-NS, Dam, Hha and TlpA. These plasmid-encoded putative regulators are termed Sfh, DamR27, HhaR27 and TlpAR27 respectively. A role is shown for Sfh, HhaR27 and TlpAR27, but not DamR27 in modulating the conjugative transfer of pSf-R27 at 30°C.