FIG. 2.

Genetic organization of the replication and partitioning regions of pCD1. (A) The replication region contains four genes (repB, copA, tap, and repA) and an origin of replication (oriR). Black boxes indicate the promoter regions for repB and repA; the promoter region for copA is not shown. (B) The par region possesses two putative trans-acting genes (sopA and sopB) and a putative DNA binding site (sopC). Arrowheads within the promoter region show the locations and orientations of short, imperfect repeats. The six 45-bp direct repeats that compose sopC are shown as open boxes, with the locations of five 16-bp inverted repeat structures designated by arrowheads. RBS, ribosome binding site. For both panels, arrows indicate the directions of transcription of individual genes, while locations within pCD1 are indicated by numbers that follow the numbering system in Fig. 1.