Figure 3
Depletion of TBP and TAFII135 is abrogated in the presence of protease inhibitors MG132 and ALLN. A. Replica plates of cells were treated with T-RA or vehicle and after 3, 4, 5, 6, and 7 days MG132 was added overnight (12 hours) and extracts then prepared designated day 4 to day 8 as indicated above each lane. TAFII135, TBP and TAFII55 were detected by immunoblotting. B. An experiment analogous to that shown in panel A was performed using the protease inhibitor ALLN. C. Measurement of the intracellular level of TAFII135. In lanes 1-3 cell extracts were made in the absence of MG132. In lanes 4-5 cells were resuspended in extraction buffer containing 50 μM MG132. D. Coordinate degradation of TBP, TAFII135 and the RARγ2. Cell extracts were made on the days indicated above each lane from T-RA treated or untreated cells and the presence of TBP, TAFII135, and the RARγ2 was detected by immunobloting. The native RARγ and the phosphorylated species (pRARγ) are indicated along with a breakdown product indicated by *. A slower migrating species of TAFII135 seen after 48 hours is indicated by -.