FIG. 5.

C2C12 cells lacking NF-κB exhibit a growth defect and changes in pRb phosphorylation. (A) Total RNA was prepared from C2C12 parental, vector control, or IκBαSR proliferating myoblasts, and Northern analysis was performed to detect the expression of Hes-1 or Id-1 genes. (B) C2C12 parental, vector control, or IκBαSR myoblasts were plated in triplicate in 10-cm plates and maintained in GM for 3 days. Every 24 h, the total cell number was determined by trypsinization and trypan blue exclusion. (C) C2C12 vector control (V) or IκBαSR cells (I) were induced to differentiate for up to 24 h. At the indicated times, cell lysates were prepared with lysis buffer containing phosphatase inhibitors and Western blotting was performed to probe for the hypo- and hyperphosphorylated forms of Rb with a monoclonal antibody (14001A; Pharmigen).