Western blot was performed as previously described[23 (link)]. Antibodies used were against c-Myc (BD Pharmingen), TRIM3 (GeneTex), β-actin, serving as a loading control (Santa Cruz Biotechnology and GeneTex), p21cip, p27kip1, Cyclin D2, Notch, Numb, Hes1, and MS1 (Musashi)(all Cell Signaling). Goat-anti-mouse IgG or goat-anti-rabbit IgG conjugated to horseradish peroxidase (Bio-Rad) were used as secondary antibodies. Enhanced chemiluminescence (ECL) was used for detection (Thermo Scientific).