Fig. 2. Effect of heat shock on translation and polysomes. (A) Changes in translation during heat-shock treatment. Cells were labelled for 20-minute windows at 27°C and during a heat-shock time course followed by recovery at 27°C. An autoradiograph of the SDS-PAGE analysis is shown. Two polypeptides with unchanged synthesis are marked with solid arrows. Examples of proteins that have reduced synthesis after 5 hours recovery are marked with dashed arrows. The stained gel was used to control for equal loading (bottom). One lane of the gel has been removed. (B) Changes in polysomes during heat shock treatment. Absorbance profiles at 254 nm of sucrose density gradients of cells incubated at 41°C for 15 and 30 minutes. 50 mM EDTA was added to the cell lysate to dissociate polysomes. Representative results from several experiments are shown.