Fig. 4. Association of huntingtin with microtubules in 3T3 cells. 3T3 cells were double stained with an antibody raised against the first 17 amino acid residues of huntingtin (green) and the monoclonal 3F3G2 anti-ß-tubulin antibody (red). Nuclei were counterstained with Hoechst (blue). (A) Before treatment with nocodazole huntingtin and tubulin immunoreactivity largely overlaped. (B) After addition of nocodazole to the culture medium, microtubules were disrupted and both huntingtin and tubulin acquired a patchy and diffuse distribution. Arrows show fragments of microtubules to which huntingtin has remained attached. Bar, 10 µm.