Mukerji P, Greener A, Filutowicz M
Department of Bacteriology, University of Wisconsin, Madison 53706.
J Bacteriol. 1992 Jul;174(14):4777-82. doi: 10.1128/jb.174.14.4777-4782.1992.
A novel source of transcription has been detected in the replication region of plasmid R6K by using fusions involving the galK reporter gene. The -35 and -10 consensus RNA polymerase binding sites were identified in the region overlapping the binding sites for the R6K-encoded replication protein pi. Transcription from this promoter, designated P2, is repressed in vivo by pi-protein levels that are inhibitory for replication. Promoter-down mutations in P2 induced in vitro by bisulfite mutagenesis result in a reduced copy number of a beta-replicon but not of a gamma-replicon. Implications of the role of P2 in R6K replication are discussed.