FIG. 1.

Effects of N- and C-terminal truncations in Brf on the TFIIIC-independent assembly of B′ (Brf plus TBP)-DNA and TFIIIB-DNA complexes. (a) The 75-bp TA-30-B6 probe for EMSA for TFIIIC-independent assembly of TBP, Brf, and B". (b) EMSA for TFIIIB-DNA complex formation. Ten femtomoles of the TA-30-B6 probe was incubated with 10 fmol of TBP, 50 fmol of full-length Brf or the indicated truncated Brf, and B" (1× = 50 fmol), as indicated above each lane. Reaction conditions were otherwise as specified in Materials and Methods, and electrophoresis was done in Mg²⁺-containing native gels. Control reactions (not shown) demonstrated that Brf-DNA complexes did not form in the absence of TBP. TBP-DNA, B′-DNA, and TFIIIB-DNA complexes are identified at the right.