Figure 5. TGFβ, but not hypoxia, induced cell cycle arrest is SMAD4 dependent.

A. CB CD34⁺ cells were transduced with vectors expressing short hairpins against SMAD4 and luciferase, sorted and cultured for 24 hours under normoxic and hypoxic conditions. Cells were then stimulated for 3 hours with 1 ng/ml TGFβ and Q-RT-PCR was performed for SMAD7 and RGS1. A representative experiment out of 3 independent experiments is shown, error bars indicate standard deviation of PCR performed in triplicate. B. CB CD34⁺ cells were transduced as in A but now cultured for 24 hours under normoxia (left panel) and normoxia versus hypoxia (right panel) and subsequently treated with TGFβ for 24 hours. Cell cycle distribution was measured using Hoechst staining. C. Schematic representation of the 2,5 kb upstream promoter region of RGS1, RGS16 and CDKN1C.