Activation of expression of the EBP50 gene in F9 cells expressing Dox-induced HNF4α. (A) F9 L32T2:HNF4α clone 8 cells were exposed to 1 μg/ml Dox for 0, 12, 24, and 48 h (lanes 1, 2, 3, and 4, respectively). 1 μg of total RNA from the cells was subjected to RT-PCR analysis for the indicated genes. PCR was performed for 17 (36B4), 22 (ezrin, radixin, and EBP50), or 23 (moesin) cycles. (B) Cells were treated for 48 h with 0, 50, 200, and 1,000 ng/ml Dox (lanes 1, 2, 3, and 4, respectively). PCR was performed as in A. (C and D) RT-PCR analysis was performed as in A and B for three independent experiments. The mRNA levels were normalized to the corresponding 36B4 levels and expressed relative to the amount present in cells grown in the absence of Dox, which was taken as 1. Values represent the mean ± SD (error bars; n = 3).