Fig. 1. Co-purification of huntingtin and ß-tubulin from lymphoblast and brain extracts. A whole lymphoblast extract from a patient with juvenile Huntington's disease and a rat brain extract were incubated in the presence of either the MAB 2166 anti-huntingtin (A) or the 3F3G2 anti-ß-tubulin (B) antibody coupled to magnetic beads. After several washes, the bound material was eluted. Equal amounts of the whole extract (WE) and of the immunopurified material (IP) were then examined by immunoblotting, using either an anti-huntingtin, an anti-ß-tubulin or an anti--tubulin antibody. In both lymphoblasts and brain the anti-huntingtin antibody purified specifically huntingtin and ß-tubulin. Reciprocally the anti-ß-tubulin antibody purified ß-tubulin and huntingtin. Neither ß-tubulin nor huntingtin were immunopurified when the corresponding specific antibodies were omitted from beads.