Inhibition of spindle elongation in permeabilized mitotic cells by erythro-9-[3-(2-hydroxynonyl)] adenine

Abstract

Studies using living cells^1,2 and experimental manipulation of permeabilized mitotic cells^3,4 demonstrate that the movement of anaphase chromosomes consists of two physiologically distinct events: chromosome movement to the spindle poles (anaphase A) and separation of the poles via spindle elongation (anaphase B). Shortening of kinetochore-attached microtubules is associated with anaphase A and rearrangement and lengthening of the polar microtubules, especially those found in the spindle midzone, with anaphase B^5,6. It has been suggested that interactions between microtubules, mediated by dynein-like cross-bridges similar to those found in flagella, may be the mechanochemical system responsible for anaphases A and B^7,8. Recently Bouchard et al.⁹ have demonstrated that erythro-9-[3-(2-hydroxynonyl)]adenine (EHNA), a protein carboxyl-methylation inhibitor, is a specific inhibitor of flagellar beat and dynein ATPase activity. I have now investigated the possibility that dynein-like ATPases have a role in anaphase by adding EHNA to permeabilized cell models in conditions compatible with maintenance of anaphases A and B after lysis^3,4.I find that EHNA blocks anaphase B but not anaphase A. These results are consistent with the involvement of a dynein-like ATPase in spindle elongation.