Mapping of the Fbw7 dimerization domain (2). A: Analysis of C-terminal truncation mutants. Fbw7α was terminated after 70, 80, 90, and 100 amino acids of the common region (schematic below) and assayed as in A. The 9E10 blot (for detection of Myc-tagged Fbw7α) was subsequently probed with Flag antibody. B: Short deletion mutants eliminate dimerization. Same assay, except that two short deletion mutants were tested for their binding to full length Myc-tagged Fbw7α. The amino acid numbering of the deletions in full-length Flag-Fbw7α again corresponds to their positions in the common region. C: Schematic of Fbw7 splice forms including their WD40 repeats, F-box, and dimerization domain.