Fig. 4.

Kinetics of p45 turnover during MEL differentiation. (A) Amount changes of specific proteins and RNAs during MEL cell differentiation. The levels of different proteins and RNAs in MEL cells without and with DMSO induction for 24–72 h were analyzed by WB with appropriate antibodies and analyses for the expression of p45, βmaj, ALAS-E, PBGD, Bach1, and GAPDH genes by Northern blotting. (B) DMSO-induced disappearance of poly-ubiquitination and proteasome-mediated degradation of p45 in MEL cells. MEL cells were treated with 20 μM MG132 for 1 h after DMSO induction for 24, 48, and 72 h, respectively, and then analyzed by WB with anti-p45 and anti-tubulin antibodies. The WCE in the right panel were prepared from MEL cells induced with DMSO for 48 h followed by treatment with anisomycin and then, analyzed by WB.