Fig. 3. dnALK2, dnALK3, dnALK6, dnBMPRII, dnActRII and dnActRIIB inhibited BMP6-induced late stage of osteogenic differentiation and Smads signaling activation of MPCs. (A) C3H10T1/2, C2C12 and BMSCs were co-infected with Ad-BMP6 and AdR-dnR. Matrix mineralization was assessed at 21 days post infection by Alizarin Red S stain. Magnification, 100×. (B) C3H10T1/2 were co-infected with Ad-BMP6 and AdR-dnR. OPN expression was assessed at 12 days post infection by immunocytochemical stain. Magnification, 100×. (C) C3H10T1/2 were co-infected with Ad-BMP6 and AdR-dnR. Smad1/5/8 transcription activity was assessed at indicated time point post infection by luciferase reporter assay. **P ＜ 0.01 vs RFP. (D) C3H10T1/2 were co-infected with Ad-BMP6 and AdR-dnR. Phosphorylation of Smad1/5/8 was detected at 24 hours post infection by Western blot.