Expression of pPRLR in transiently transfected CHO-K1 cells. (A) Expression of PRLR mRNA was determined by northern analysis of 5 μg total RNA from CHO-K1 cells transfected with 1 μg of each PRLR. The blot was probed with a fragment of the pPRLR ECD. Migration of the RNA ladder (M) is indicated. Negative controls (Neg) were from untransfected cells. (B) Sybr Green RT-PCR of PRLR mRNA expression in transfected CHO-K1 cells normalized for 18S rRNA expression. Cells were transfected with 250 ng of each PRLR expression construct DNA. Transfections were performed in duplicate and data are mean ± S.E.M. (n = 2).