Fig. 4. Polysome profile (A) and pulse–chase (B) analyses. (A) Polysome profiles of GAL::rcl1 (panels b–d), rcl1-1 ts (panels e–f) mutant strains and a wild-type (panel a) strain grown under permissive and/or restrictive conditions. Time of growth on YPD or at the restrictive temperature is indicated. Polysome profiles of wild-type cells grown at 30°C (panel a), and at 25 and 37°C (not shown) are similar. (B) Pulse–chase labelling of rRNA with [methyl-³H]methionine (lanes 1–12) and [³H]uracil (lanes 13–18) in the wild-type and GAL::rcl1 strains. Labelling (3 min) was performed following 5 h growth on YPD.