FIG. 4.

Transient expression of Hsp70 does not affect luciferase degradation after heat shock. OT70 cells were transiently transfected with a plasmid encoding either cytoplasmic luciferase (Cyt-luc) or nuclear luciferase (Nuc-luc). At 24 h after transfection, the cells were grown for another 24 h in medium containing 3,000 ng of tetracycline/ml (+tet) or no tetracycline (−tet). Next, they were either left unheated (C, lane 1) or were heated for 30 min at 45°C and incubated for 0 to 2 h at 37°C (lanes 2 to 5) as indicated. Cycloheximide (20 μg/ml) was present during the heat and recovery period. Samples were obtained at the indicated time points, and luciferase was detected by a polyclonal antibody to luciferase by Western blot analysis.