FIG. 3.

Heteromultiraer analysis of complex III. Extracts were prepared from heat-shocked cells carrying either truncated HSF (HSF^1–583) or full-length HSF (HSF^1–833), each with the M232V mutation. The extracts were used alone, or mixed, in a gel mobility shift DNA binding assay using Tris-glycine gel buffer. The positions of predicted mobilities for heteromultimers formed from six HSF monomers are indicated. The HSF^1–583 expression vector was prepared by inserting a 9-base oligonucleotide carrying an in-frame stop codon into a Stul restriction site. The stop codon was later discovered to be subject to translational readthrough [see (15)]; cells carrying this plasmid express a small amount of full-length readthrough product (detectable by Western blot, not shown), which accounts for the appearance of heteromultimers in the “1-583 only” lane.