Figure 1.

Western blot analysis showing increased levels of UBF in TBP immunoprecipitates from growth-stimulated vs. quiescent cells. (A) Western blot analysis of UBF levels in TBP immunoprecipitates from SMC growth arrested in a defined SFM and stimulated with A-II, PDGF-BB, and FBS, as described in Methods. Cells were harvested and immunoprecipitations were performed as described in Methods. The blots were probed with a UBF antibody (a generous gift from L. Rothblum, Weis Research Institute, Danville, PA). Blots were detected with enhanced chemiluminescence (ECL, Amersham) according to manufacturer’s directions. (B) The same TBP immunoprecipitates assayed in A were assayed for TBP by Western blotting with a TBP antibody (Santa Cruz Biotechnology) as described in Methods. Because of a greater recovery of TBP, the loadings in B were proportionally reduced for all samples by a factor of eight, as compared with the corresponding lane in A.