FIGURE 5.

Individual lobes of CaM impair E2 stimulation of endogenous ER-α transcription. A and B, MCF-7 cells were transiently transfected with either GFP-tagged CaM-F, CaM-N, or CaM-C. Cells were cultured in phenol red-free medium for 24 h, then vehicle (EtOH, blue bars) or 100 nm E2 (red bars) was added to the medium. After incubation for 6 h, total RNA was isolated and quantitative RT-PCR analysis was performed to measure pS2 (panel A) or PR (panel B) hnRNA. The amount of RNA in each sample was corrected for β-actin RNA in the same sample. Vehicle-treated cells were set as 1. The data represent the mean ± S.E. (error bars) of an experiment performed in triplicate. C, MCF-7 cells, transfected as outlined above, were lysed and equal amounts of protein lysate were resolved by Western blotting. Blots were probed with antibodies to ER-α (upper panel) and GFP (lower panel). All data are representative of at least 3 independent experiments.