FIG. 3.

Effects of heat shock and MG132 on rates of transcription of heat shock genes. Nuclear run-on analyses of hsp70, hsp90, grp78, hsc70, and GAPDH gene transcription in control 3T3 cells (lane 1) or cells treated with MG132 for 1 and 4 h (lanes 2 and 3, respectively), heat shock (HS) at 43°C for 0.5 h (lane 4), or MG132 for 4 h followed by heat shock at 43°C for 0.5 h (lane 5) are shown. The vector corresponds to the plasmid pGEM4, used to determine level of nonspecific hybridization. The levels of transcription were determined relative to nonspecific background and the internal control, the GAPDH gene.