Figure 8.
Contribution of cytoplasmic and nuclear forces to SPB fragmentation. (A) Serial dilutions of spc110-226 haploid cells with either DYN1 or dyn1Δ (derived from TYY158). Independent isolates of the strains were serially diluted (10-fold), spotted on YPD plates, and incubated at 22, 32, 34, and 37°C. (B) Serial dilutions of control SPC110 (BSY9) and spc110-226 (SFY200) diploid cells transformed with empty vector (pGF29) or GAL-DYN1-GFP (pKB701). Cells were serially diluted (5-fold) and spotted on SD-URA and SGAL-URA. (C) SPB separation (appearance of two or three foci containing Spc97p-Venus) and SPB fragmentation (appearance of three foci containing Spc97p-Venus) were measured in spc110-226 (TYY169) and spc110-226, arp1Δ arp1td kar9Δ (TDY174-29B) cells released from α-factor to 37°C. Time is in minutes after release to 37°C. Greater than 100 cells were counted for each time point. Both Arp1p and Kar9p were inactivated because 92% of the SPBs, and SPB fragments were in the mother cell in the spc110-226, arp1Δ arp1td kar9Δ strain, compared with 55% in the mother cell of the spc110-226 strain. (D) SPB separation and fragmentation were measured in spc110-226 (TYY169) and mcd1-1, spc110-226 (TDY168-7D) cells with labeled SPBs (Spc97p-Venus) released from α-factor to 37°C. Time is in minutes after release to 37°C. Greater than 100 cells were counted for each time point.