Figure 4.

(a) TOR1 (Ser-1972 → Arg) or TOR2 (Ser-1975 → Arg) renders dominant rapamycin resistance during meiosis. Wild-type diploid SK-1 [a/α, TOR1/TOR1, TOR2/TOR2] or SK-1 with chromosomal rapamycin-resistant mutations Ser-1972 → Arg in TOR1 [a/α, TOR1/TOR1 (Ser-1972 → Arg), TOR2/TOR2] or Ser-1975 → Arg in TOR2 [a/α, TOR1/TOR1, TOR2/TOR2 (Ser-1975 → Arg)] cells were incubated in YPD for 24 hr at 30°C with vigorous shaking. These cells were then diluted 1:50 into YPA. After 13.5 hr of further incubation, the cells were washed twice with sterile water and resuspended into SPM supplemented with 100 nM rapamycin. The samples were analyzed as in Fig. 3a. (b) The kinase activities of Tor proteins are required for rapamycin-sensitive meiotic functions. Diploid SK-1 strains containing a control plasmid, a plasmid expressing TOR1 (Ser-1972 → Ile), TOR1 (Ser-1972 → Ile, Asp-2294 → Glu), TOR2–1 (Ser-1972 → Ile), and TOR2–1 (Ser-1972 → Ile, Asp-2294 → Glu), respectively, were incubated in selection medium for 36 hr to saturation, diluted 1:50 into YPA for another 13 hr before being resuspended into SPM supplemented with different concentrations of rapamycin for a further 13.5 hr. The results represent an average of three different experiments (n = 250).