Visualization of detyrosination along single microtubules reveals novel mechanisms of assembly during cytoskeletal duplication in trypanosomes

Abstract

We have been able to use immunogold labeling with monoclonal antibodies specific for tyrosinated .alpha.-tubulin to define new microtubule assembly within the T. brucei pellicular cytoskeleton. Using this approach, we have been able to visualize and define the detyrosination gradient along single microtubules in vivo. New microtubules are seen to invade the cytoskeletal array early in the cell cycle between old microtubules. In post-mitotic cells, a unique form of microtubule assembly occurs, whith very short microtubules being intercalated in the array. We propose that these are nucleated by lateral interaction with MAPs on existing adjacent microtubules. This construction pattern suggests a templated morphogenesis of microtubule arrays with semi-conservative distribution to the daughter cells.