FIG. 1.

Affinity purification and composition of the human STAGA complex. (A) Immunopurified STAGA complex. Shown is a silver stain of gradient SDS-PAGE gels containing STAGA purified from nuclear extracts of the fh:SPT3-expressing cell line (lanes 2 and 3) and mock-purified fractions derived from control HeLa nuclear extracts (lanes 1 and 4) after affinity purification on M2-agarose (lanes 1 and 2) or after successive immunopurifications M2-agarose and anti-HA antibody resins (lanes 3 and 4). The positions of fh:SPT3 and STAFs with their approximate molecular masses are indicated. (B) Identity of STAFs determined by tandem MS. n.a., not analyzed.