Effects of methylmercury and some metal ions on microtubule networks in mouse glioma cells and in vitro tubulin polymerization.

Mercury compounds and some other metal ions were investigated with respect to their effect on in vitro tubulin polymerization and on cellular microtubules in mouse glioma. In vitro tubulin polymerization was completely inhibited by 2.5 X 10(-5) M Hg2+, 5 X 10(-5) M CH3Hg+, 2 X 10(-4) M Cr3+, 2.5 X 10(-4) M Cu2+, and 5 X 10(-4) M Cd2+. Zn2+ did not affect the polymerization up to 5 X 10(-4) M. Indirect immunofluorescence study with rabbit antiporcine tubulin antibody revealed that methylmercury disrupted the microtubule network at an early stage of growth inhibition. On the other hand, in the presence of Cd2+, Cu2+, and Cr3+ at their growth inhibitory concentrations, no effects on microtubule networks were observed for the first 1 hr. These results indicate that only methylmercury affects cellular microtubules, while other ions seem to interfere with other sites in the cells, although these ions showed the ability to depress in vitro tubulin polymerization.