Rotating microtubules as a basis for anaphase spindle elongation in diatoms.

The separation of the spindle poles during anaphase in diatoms can easily be explained by contrarotating microtubules in the two half spindles. A model is presented demonstrating that in such a situation, the electron microscopically observed tetragonal pattern of the antipolar microtubules in the overlap region is the only means to achieve minimal frictional resistance. The consequences of the microtubule-rotating concept are discussed to comparison with other models (e.g. microtubule/microtubule-sliding).