FIG 7 .

A cartoon summarizing the effect of additional rctA sites on chromosome dynamics of V. cholerae. The nucleoid is shown in yellow, oriI in green dots, and oriII in red dots. In wild-type cells (top), oriI replicates near a cell pole and oriII near the cell center but at a time later than oriI. Replication and segregation of oriI are not disturbed by any of the rctA sites unless chrII is lost from cells (see Fig. 4E to G versus H to J). The mislocalization of oriI apparently results from chromosome condensation that follows upon the loss of chrII due to unknown reasons. The presence of RctB sites delays oriII firing, since a single oriII focus was seen in longer cells (Fig. 4M). The presence of parSII sites does not delay oriII firing but mislocalizes oriII, as two oriII foci were seen even in small cells (Fig. 4N). The results in the presence of intact rctA are a composite of the effects seen with RctB and parSII sites separately (Fig. 4L).