Figure 5: TAF8 promotes TAF2 incorporation in TFIID.

(a) TFIID components studied are shown as bar diagrams. Predicted low-complexity regions of the proteins are coloured in grey. A black bar denotes the TAF8 NLS. C-terminally truncated TAF8 (TAF8ΔC), which was used to reconstitute the 7TAFΔ complex, is depicted on the right. Numbers denote first and last amino acids for each protein. (b) Impact of the TAF8 truncation on TAF2 binding to 7TAF complexes. SEC elution profiles for indicated proteins and protein complexes are shown (top). Corresponding SDS–PAGE gel sections of peak fractions of each run are shown (bottom). Protein size markers are shown on the left; protein identities on the right. (c) Three-dimensional single-particle EM reconstruction of negatively stained 8TAF complex (grey mesh) superimposed on 7TAF complex (yellow, from ref. 12) is shown in two views related by a 90° rotation as indicated (arrow). Difference density attributed to bound TAF2 is highlighted in blue. (e) Protein–protein crosslink maps for the 7TAF complex (left) and the 8TAF complex (right) are shown. Circle sizes represent relative molecular weights of each protein. Black lines connect crosslinked proteins. Grey bars superimposed on black lines indicate crosslink frequencies ( www.crosslinkviewer.org). Original images corresponding to the gel sections shown in Fig. 5b (bottom panel) are provided in Supplementary Figure 8.