Fig. 5. SIAH1 mediates degradation of BOB.1/OBF.1. (A) Western blot of NIH 3T3 cells transfected with BOB.1/OBF.1 alone or together with SIAH1. Myc-tagged MyoD was used as a loading control. (B) Northern blot of the same transfected cells. (C) The BOB.1/OBF.1 half-life time becomes decreased by SIAH1. NIH 3T3 cells were transfected as described above. After pulse labeling the half-life time of BOB.1/OBF.1 was measured. (D) Western blot of NIH 3T3 cells transfected with vectors containing BOB.1/OBF.1, SIAH1 or increasing amounts of the myc-tagged SIAH1 C-terminal part. Mini-myc was used as a loading control.