Fig 2.

 Northern blot analysis of total cellular ribonucleic acid (RNA) isolated from Chinese hamster HA-1 cells exposed to a heat shock of 15 minutes at 45°C (heat), 100 μM sodium arsenite for 55 minutes (arsenite), or continuous exposure to a medium containing 2.5 mg/mL of azetidine for up to 24 hours (azetidine). The numbers above each lane indicate the number of hours of recovery at 37°C following exposure to heat shock or sodium arsenite, or the number of hours of treatment with azetidine-containing medium at 37°C, whereas (–) represents the control, nontreated cells. Exposure to the various stresses, and preparation and analysis of total cellular RNAs were performed as described under “Materials and Methods”