Traf7 expression positively correlates with pRB phosphorylation state. (A) Immunofluorescence of MHC expression in myoblasts ectopically expressing cyclin D1 and depleted of Traf7 (iTraf7) and differentiated for 48 h. Scale bars, 40 μm; magnification × 10. Histogram shows normalized MHC signal in iTraf7 cultures compared with that of control. Error bars indicate s.e.m. values; P-values for three independent experiments. (B) pRB and cyclin D1 immunoblots on 100 μg of lysate. DAPI, 4′,6-diamidino-2-phenylindole; MHC, myosin heavy chain; NS, nonspecific; pRb, hypo-phosphorylated pRb; ppRb, hyper-phosphorylated pRb.