Fig. 3. RT-PCR analyses of muscle- and bone-associated genes. Upper panel, total RNA was purified from MyoD^-/- and WT cells either before shifting them to differentiation media (day 0) or after a 3-day treatment with or without BMP-7 (400 ng/ml). Target mRNAs were analyzed by RT-PCR. ß-Actin levels indicate that similar amounts of RNA were used for each time point. Arrows indicate Runx2 transcripts. Lower panel, expression of Osx and the housekeeping gene ß-actin in a second cDNA synthesis from the RNA used in the upper panel.