Fig. 1. Genetic interactions of S. pombe cps1-12 mutant with the actin mutant cps8-188 and with cdc septation mutants. Phase-contrast and Calcofluor white UV staining micrographs of log-phase cells grown on YES liquid medium at 25°C and shifted to different temperatures. Cells are shown grown at the temperature that reveals in each case the most apparent difference between single and double mutant phenotypes (8 hours at 30°C for cps8-188, 8 hours at 31°C for cdc16-116 and 6 hours at 34°C for cdc14-118 single and double cps1-12 mutants). The phenotype of the cps1-12 cps8-188 double mutant is more aggravated than that of the corresponding single mutants, while the phenotype of the cps1-12 cdc14-118 double mutant resembles that of the cdc14-118 single mutant, and the phenotype of the cps1-12 cdc16-116 double mutant is similar to that of the cps1-12 single mutant. The cps1-12 single mutant cells were grown at 34°C, but a weaker phenotype was obtained at 30 or 31°C. Cells were centrifuged, suspended in 50 µg/ml Calcofluor white and directly observed for phase-contrast and Calcofluor white staining.