Figure 4.

Estrogen-dependent activation of the bkj gene. Quail embryo fibroblasts transfected with various RCAS expression vectors were treated with (+) or without (−) estrogen as indicated for 48 hr (Left). Ten micrograms of total RNA per lane was analyzed by Northern blotting. The blot was hybridized with the ³²P-labeled bkj cDNA sequence. Equal loading was confirmed by rehybridization with a glyceraldehyde-3-phosphate dehydrogenase probe. The sizes and positions of molecular mass markers are indicated on the left. Cells were grown in the presence (+) or absence (−) of 50 μg/ml cycloheximide either with (+) or without (−) 2 μM estrogen (Right). The hormone was added to the cultures 15 min later than cycloheximide. Cells were harvested 5 hr after addition of hormone. Fifteen micrograms of total RNA per lane were analyzed by Northern blotting.