Cells with reduced cohesion have impaired chromosome segregation.

(A) Separation velocity is reduced in cells overexpressing Topo IV. Cells bearing a tetO array at gln and expressing TetR-mCherry were transformed with pDB332, a weak Topo IV expression plasmid (Topo IV-OE), or the empty vector pBAD322-kan (Vector), grown to log phase in AB succinate +CAA, induced for two hours, placed onto agarose pads and imaged by time-lapse microscopy. Inter-focus distance was measured every 10 minutes through one cell cycle. Time zero represents the first time point at which two foci appeared. Regression line (black) is shown for 10 independent cells (red). (B) Separation velocity is reduced in ΔseqA cells. Cells were grown and analyzed as above. (C–D) Topo IV overexpressing cells exhibit abnormal gln (C) and dnaB (D) focus positions. Inter-focus distances were determined in exponentially growing cells by FROS. Regression line (black), and mean (x) and mode (Md) inter-focus distances are shown for each histogram (n = 500). (E) Graphical summary of gln and dnaB segregation data in cells with normal or reduced cohesion (see Text for details).