FIG. 9.

Transcriptional regulation of the transfer functions of the S. lividans plasmid pIJ101. The GntR-type repressor KorA represses the transcription of tra/kilA and korA by binding to the overlapping promoter regions (204). The KilB repressor KorB is synthesized as a 10-kDa protein and subsequently processed to a 6-kDa molecule which binds to the kilB promoter 50-fold more efficiently than to the korB promoter (206). By an unknown mechanism, KorA also overrides the lethal action of unregulated kilB expression.