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. 2003 Mar;23(6):1994–2008. doi: 10.1128/MCB.23.6.1994-2008.2003

FIG. 7.

FIG. 7.

Interaction between ERα and PRB in COS-7 cells. COS-7 cells were transiently cotransfected with ERα and various PR expression vectors (PRB wild type, PR ΔERID-I, PR ΔERID-II, or PR ΔERID-I+II). (A) The expression of ERα and the different PR constructs was verified by immunoblotting of total cell lysates with anti-ERα or anti-PR antibodies. (B) Coimmunoprecipitation of ERα and PR. Cell lysates were immunoprecipitated with anti-ERα antibody or nonspecific IgG (control antibody [Ctrl Ab]). Each immunoprecipitate was analyzed with anti-ERα or anti-PR antibodies. ERα and PRB bands are indicated by arrows. (C) Effect of progestins on Erk activity. Cells were treated for 5 min with 10 nM R5020 (lanes 5 to 8 and 13 to 16) or with the ethanol (lanes 1 to 4 and 9 to 12). Cell lysates were prepared, immunoprecipitated with anti-Erk1/2 antibodies, and assayed for MAP kinase activity with MBP as a substrate as described previously (30). The left panel (lanes 1 to 8) shows the results obtained with preimmune serum as a control.