Fig. 6. The SIN is not required for timely expression of ace2⁺ or mid2⁺. (A) cdc7-24 (KGY2061) cells were synchronized at the G2-M boundary by centrifugal elutriation. The synchronous population was shifted to 36°C. Cell pellets were collected every 20 minutes beginning 30 minutes after the shift. RNA recovered from the pellets was used for northern blot analysis of mid2⁺, ace2⁺ and his3⁺ (loading control). An aliquot of cells was also collected at each time point, fixed in ethanol and stained with DAPI in order to microscopically visualize the cell nuclei and monitor progression through the cell cycle. (B) mid2-GFP cdc16-116 (KGY741) cells were synchronized by centrifugal elutriation and treated as in (A). The percentage of binucleate cells (BN) was determined by DAPI staining. Septation index was monitored throughout the time course.