Figure 9.

Crosstalk between the replication and mobilization modules of plasmid pMV158. Regulatory circuits include proteins and the antisense RNAII. Protein RepB is the initiator of leading strand replication (blue) that interacts with its target DNA (the origin of replication, dso). The copG–repB mRNA encodes also the transcriptional regulatory protein CopG (purple) that binds to and represses transcription from the single Pcr promoter. The second control element is the antisense RNAII, which acts post-transcriptionally by pairing with the translation initiation signals of the essential repB mRNA. MobM (orange) is involved in the initiation of plasmid conjugative transfer (relaxase activity). In addition, it controls its own synthesis by binding to promoter Pmob and hindering the binding of the host RNA polymerase. Further, as reported here, MobM acts as a regulatory element in the plasmid replication control circuit, because it represses transcription of rnaII from promoter PctII. Positively regulated circuits are indicated by a + in green, whereas negatively regulated circuits are indicated by a − in red.