Fig. 1. The cdc2-as mutant is sensitive to analogue. (A) Wild-type and cdc2-as cells were grown in YE medium to early exponential phase and analogue was added to a concentration of 1 µM; the controls received an equal volume of DMSO. Cell number was determined at intervals. (B) Micrographs of the cells described in panel A, stained with DAPI and Calcofluor. Cells were incubated for 3.5 hours at 25°C after addition of analogue. (C) FACS analysis of the cells described in (A). HU 2.5h are cells treated for 2.5 hours with 12 mM hydroxyurea, to generate G1 and G2 peaks as 1C and 2C references. Note that in exponential growth, an S. pombe FACS profile shows only a single peak, corresponding to 2C DNA content. This is because G1 is very short and cells have completed S-phase before the daughters separate. (D) Samples from the experiment shown in panel A were fixed and stained with Rhodamine-conjugated phalloidin to reveal F-actin. Scale bars: 10 µm.