A monoclonal antibody that binds to Mt+ flagellar adhesion molecules of Chlamydomonas

The authors' laboratory recently produced a monoclonal antibody, 2b40, that specifically blocks the adhesiveness of mt+, but not mt-, gametes during the mating raction of the biflagellated alga, Chlamydomonas reinhardtii . To learn more about flagellar adhesion and the loss of adhesiveness that normally occurs during the mating reaction the authors have used 2b40-derivatized sepharose beads which bind only mt+ and not mt-gametes. In the presence of the protein synthesis inhibition, cycloheximide (CH), mt+ gametes adhering to 2b40-coated beads lost their ability to adhere to the beads and to mt-gametes after 1-2 hours, whereas cells in the absence of inhibitor adhered to the beads for at least 8-10 hours. The adhesiveness of mt+ gamates incubated without beads was unaffected by the inhibitor. These results suggested that there was an adhesion-induced loss of mt+ flagellar adhesion molecules. Experiments to determine the fate of the lost mt+ adhesion molecules showed that the beads that had been with mt+ gametes had acquired the ability to bind mt- gametes even in the absence of CH.