Fig. 3. PTHrP induces BMPr1a mRNA expression in vitro and in vivo. (A) BMPr1a mRNA detected by qRT-PCR in C3H10T1/2 cells treated with or without 10^-7 M PTHrP overnight (n=3 experiments). (B) qRT-PCR for BMPr1a mRNA in ventral skin from cultured wild-type E13.5 embryos treated with or without 10^-7 M PTHrP overnight (three experiments with two to three embryos per treatment). Note that PTHrP increases BMPr1a expression. (C) qRT-PCR for BMPr1a mRNA in the ventral skin from E18.5 K14-PTHrP transgenic and wild-type control mice. BMPr1a expression is higher in K14-PTHrP epidermis (n=4 experiments). (D) qRT-PCR for BMPr1a mRNA in mammary buds microdissected from either wild-type or PTHrP^-/- embryos on E15.5. Expression is reduced in the PTHrP knockout buds compared with wild-type controls. RNA was from pooled buds (50-100 buds per sample). (E,F) Dark-field (E) and corresponding light-field (F) images of in situ hybridization for BMPr1a expression in an E15.5 wild-type mammary bud. Arrowhead points to the epithelial bud. The BMPr1a gene is expressed at a low level throughout the mesenchyme, but appears not to be expressed within the mammary epithelium.