Fig. 3. Gel filtation analysis of XBub3 protein complexes in egg extracts. A CSF egg extract was fractionated by Superose-6 gel filtration chromatography (see Materials and Methods). Protein-containing fractions were analysed by western blotting with antibodies to XBub1, XBubR1, XBub3, XMad1 and XMad2 proteins. No protein was detected by Ponceau staining or western blotting prior to fraction 14 and after fraction 40. The elution positions of molecular weight standards are indicated.