FIG. 2.

Immunoprecipitation of the TFIIIC2 complex and immunodepletion of TFIIIC transcription activity by anti-hTFIIIC90 antibodies. (A) Immunoprecipitates from HeLa nuclear extracts treated with preimmune (P) and immune (I) anti-hTFIIIC90 antibodies in BC500–0.1% NP-40 were subjected to Western blot analysis. The polypeptides were detected by a mixture of antibodies against hTFIIIC220, -110, -102, -90, and -63. (B) Nuclear extracts treated with preimmune (P) and immune (I) anti-hTFIIIC90 antibodies were used for in vitro transcription assays with the 5S, VAI, and tRNA templates (lanes 1 to 6) and with the pG₅HMC₂AT and pMLΔ53 templates (lanes 11 to 14). The immunodepleted extract employed for lanes 1 to 6 retained a small amount (<10%) of hTFIIIC90 (data not shown). The immunodepleted extract employed for lanes 7 to 10 had no detectable hTFIIIC90 (data not shown), and immunopurified TFIIIC (the same preparation analyzed for Fig. 1B) was added in lanes 9 (1 μl) and 10 (2 μl).