Expression of Flag-tagged mutant BRG1 or hBRM does not affect heat-shock-mediated activation of hsp70. Cell lines were placed into media either containing or lacking tetracycline. Sixty-eight hours later, half of the samples were placed at 32°C. At 84 h postpassage, the media from the cells placed at 32°C were replaced with media preheated to 42°C. The cells were then placed at 42°C for 2 h. Cell lines that had remained at 37°C were treated with 100 μM sodium arsenite for 8 h. Total cellular RNA was prepared, protein extracts were made from duplicate plates, and RNA and Western analyses were performed as described for Fig. 5. M, mock-treated cells; HS, heat-shocked cells; A, arsenite-treated cells. (E) Quantification of the decrease in activation of hsp70 by heat shock in the presence of the dominant negative proteins. Data points with error bars represent the average of three to five experiments; those without error bars are the average of two experiments.