Figure 4.

Sister replisomes migrate to separate cell halves in the absence of locus segregation. (A,B) Snapshot analysis of ori1 and replisome (Ssb-Ypet) in parE^ts strain at 30°C and 42°C (2 h). (C) Time-lapse analysis (5 min). Ten parE^ts cells were switched to 42°C (35 min) and then followed at 42°C by time lapse, and the mean positions of the ori1 foci (either a single focus or transient pair of closely spaced foci) and Ssb-Ypet foci are shown (bars show standard errors). (D) ori1 separation in parE^ts at 42°C (data from C) compared with ori1 separation in TopoIV⁺ cells grown at 42°C (not shown). The indicated time intervals are the time from replisome appearance to the last point at which a replisome was present. (E) The separation between sister replication forks after initiation from the data presented in C is compared with a similar experiment using wild-type cells grown at 37°C.