JUNCTIONS BETWEEN MICROTUBULE WALLS

We have studied lateral associations of microtubule walls by electron microscopy and image analysis. In negative stain they are observed as composite sheets having two or more domains usually facing in opposite directions. Thin sections show a variety of complex tubular arrays including structures resembling flagellar doublets and centriolar triplets. It appears that protofilaments can combine in two distinct modes, one leading to microtubule walls, the other forming junctions between walls. Both kinds of bonds seem to be inherent properties of tubulin and not of microtubule-associated protein. © 1979.