Interaction of methylmercury with microtubules in cultured cells and in vitro.

The effects of methylmercury (MeHg) on cytoplasmic microtubules in cultured fibroblasts and on the in vitro polymerization of microtubules were examined. MeHg caused disruption of cellular microtubules in a concentration- and time-dependent manner. Addition of the metal-chelating agent, dimercaptosuccinic acid (DMSA), both prevented and reversed the effect of MeHg. Comparisons of the cellular levels of mercury and microtubule integrity indicated that microtubules dissociated at levels higher than 0.6 microgram Hg/mg protein. In vitro polymerization was also directly inhibited by MeHg; this effect was prevented by the addition of DMSA.