We used P19 cells to test specificity of TGFβ induction of Bptf protein levels. P19 cells were grown in 10% FBS, DMEM, 2 mM glutamine, penicillin and streptomycin. Ligands were added at the following concentrations; TGFβ1 (R&D Systems) at 5 ng/ml, FGF4 (R&D Systems) and heparin at 25 ng/ml and 1 ug/ml respectively, BMP4 (R&D Systems) at 10 ng/ml and Wnt3a or L cell control conditioned medium at 1∶1 with 10% FBS, DMEM, 2 mM glutamine, penicillin and streptomycin. Cells were incubated overnight and harvested for protein with TriReagent reagent (Sigma) according to manufacturers procedures. Bptf Western blotting was performed as described above.