mcs1 delays the initiation of
mitosis. (A) mcs1-77 is synthetically lethal with
cdc25-22. Wild-type, mcs1-77,
cdc25-22, and mcs1-77 cdc25-22 cells were
grown on YEPD at 28°C and then streaked onto YEPD plates at 28, 31,
or 36°C, and the growth of the strains was monitored after 3 d
at these temperatures. (B) mcs1-77 cdc25-22 arrested
cells are highly elongated. mcs1-77 cells were crossed
to cdc25-22 cells, and the resulting asci were subjected
to tetrad dissection on YEPD plates at 31°C. Colonies from a
tetratype that were genotypically mcs1-77 (left),
cdc25-22 (middle), or mcs1-77 cdc25-22
(right) were visualized after 2 d of growth at 31°C.