Nucleotide sequence of the rep gene of staphylococcal plasmid pCW7.

Previous heteroduplex mapping studies showed that staphylococcal plasmid pCW7 belongs to the pT181 family of small antibiotic resistance plasmids which replicate by a rolling-circle mechanism. Replication in each case is initiated at the plasmid origin (ori) by a plasmid-encoded protein. Rep, which makes a sequence-specific single-stranded nick to form a covalent Rep-ori replication intermediate. A comparison of sequencing results for the repN gene of pCW7 with data for the products of five other homologous rep genes allows a prediction to be made of the segments of the primary structure of Rep which are likely to be responsible for plasmid-specific recognition of the ori region by each Rep protein.