FIG. 8.

Coimmunoprecipitation of TFIIIC subunits from crude extracts. Immunoprecipitations with anti-HA antibodies were performed as described in Materials and Methods with crude extracts from the wild-type (WT) strain or strains expressing HA-tagged versions of τ138, τ131, and τ95 (HA-τ138, HA-τ131, and HA-τ95, respectively). Proteins eluting with the synthetic peptides were subjected to SDS-PAGE, transferred to a membrane, and probed successively with polyclonal antibodies directed against τ95, τ55, τ131, and τ91. Immune complexes were revealed with an ECL kit and quantified by scanning. A value of 1 was arbitrarily given to the amounts of τ95, τ55, τ131, and τ91 subunits immunoprecipitated from the HA-τ138 crude extract and was used as a reference. On the left are indicated molecular masses (in kilodaltons) of the polypeptides probed by the antibodies noted on the right. The 75-kDa polypeptide revealed by anti-τ91 antibodies was immunologically related to τ91 (2).