1. Nuclear-free preparation Control Nuclear-free preparation DMSO Whole cell preparation Control Whole cell preparation DMSO 66 kD Supplementary Fig. 1. Western Blot analysis of the nuclear marker, Lamin B. Lane 1 and 2 show the western Blot of proteins from the nuclear-free preparation using a needle and homogenizing solution, and lane 3 and 4 show that of protein from whole cell preparation by lysis buffer and sonication.

2. Supplementary Fig. 2. Effects of ER antagonists on ER expression in whole-cell preparation. C2C12 cells were treated with tamoxifen (10-12-10-6M; panel A) or ICI 182,780 (10-12-10-6M; panel B) for 15hours. Total fractions of ER were prepared as described in the Method and subjected to Western blotting. Histograms is expressed as the percentage of control (no stimulation), averaged from five separate experiments (mean ± S.E.).

3. Supplementary Fig. 3. Effects of ER antagonists on E2-induced ER increase in whole-cell preparation. C2C12 cells were treated with E2 (10-8M) in the presence of either tamoxifen (10-12-10-6M; panel A) or ICI 182,780 (10-12-10-6M; panel B) for 15hours. Tamoxifen and ICI 182,780 were added to the culture medium 30 min prior to the administration of E2. Total and nonnuclear fractions of ER were prepared as described in the Method and subjected to Western blotting. Histograms is expressed as the percentage of control (no stimulation), averaged from five separate experiments (mean ± S.E.).