Coelution of Ikaros isoforms in a broad peak from gel filtration columns. RLm11 nuclear extracts (1 mg) were analyzed by Superdex 200 (Pharmacia) gel filtration chromatography. Five micrograms of nuclear extract (lane 1) and 45 μl of every other column fraction (lanes 2–13) were separated by SDS-PAGE and analyzed by immunoblotting, with antiserum directed against Ikaros and Elf-1. The fractions in which standard molecular mass markers elute are indicated by arrows at the top, and the bands corresponding to Elf-1 and Ikaros isoforms I, III, V, and VI are (left).