Microtubule cycle in Chlamydomonas reinhardtii: An Immunofluorescence study

Monoclonal antibodies to yeast tubulin have been used to investigate the distribution of microtubules throughout the cell cycle of the green alga Chlamydomonas reinhardtii . By indirect immunofluorescence microscopy we detect all the classes of microtubule‐containing structures previously described from ultrastructural investigations but we can now demonstrate the complex spatial and temporal relationships between the different microtubule arrays. During interphase a cortical cytoplasmic microtubule system emanates from the base of the flagellar microtubules. These microtubules become reorganised on entry into mitosis, being largely disassembled and replaced by the spindle and “metaphase band” microtubules. The “metaphase band” is shown to be not one array but two distinct sets of microtubules, each linking a spindle pole with a region of the cell cortex near the spindle equator. It persists until late telophase, when it is replaced by cortical and cleavage furrow microtubules.