Fig. 5. EMTOC formation requires SIN function. spg1.B8 cdc7.A20 double mutant cells were grown to early log-phase at 25°C before the culture temperature was shifted to 36°C. Panels show tubulin (upper panels in A-E and left in F) and DAPI/DIC images (lower panels in A-E and right in F) of the same fields of cells. EMTOCs clearly formed at 25°C (arrowheads A, B) but were not seen in the first (C) or second division (D,E) at 36°C. The profile of the nuclei in C and D show that the cells are in late anaphase B when the EMTOC would be expected to have already formed. Similarly, the nuclear profiles in E are those of a cell in which the spindle has just depolymerised. Cells at this stage should also have an EMTOC. (F) A mixed culture of cdc7.A20 and wild-type cells was processed for tubulin staining five hours after the temperature of the culture had been changed from 25°C to 36°C. EMTOCs were not observed in the long multi-nucleate mutant cells but were seen in the wild-type control cells (arrowhead).m