FIG. 7.

MEKKΔ-DA specifically increases the transcriptional activity of androgen receptor on a minimal promoter element. (a) Effect of MEKKΔ-DA on transcriptional activation of a promoter consisting of pure androgen response elements in DU145. A promoter consisting of four multimerized androgen response elements, 4X-ARE/E4-CAT (0.4 μg) was transfected into DU145 as in Fig. 6b. CAT production was analyzed by ELISA as described in Materials and Methods and by conventional CAT assay. ImageQuant software was used to analyze phosphorimager data for the conventional CAT assay. This is one representative experiment of four total. (b) Effect of MEKKΔ-DA on the transcriptional activation of a promoter consisting of ZEBRA response elements in DU145 cells. For these experiments, DU145 stably expressing androgen receptor or Neo-infected cells were transfected with the vectors as indicated: 0.8 μg of reporter plasmid, 0.8 μg of ZEBRA transcription factor, and 2.4 μg of MEKKΔ-DA or Neo vector control. The data shown were obtained with androgen receptor-expressing DU145 cells.