PLANT MICROTUBULES CAN BE TRANSLOCATED BY A DYNEIN ATPASE FROM SEA-URCHIN IN-VITRO

The latent ability of plant microtubules to translocate or slide in th e presence of motor protein was examined in a motility assay in vitro. Plant microtubules isolated from tobacco BY-2 cells moved over a glas s surface covered with outer arm 21S dynein from flagella of sea urchi n sperm with an average velocity of 3.7 mu m s(-1). This velocity was similar to that of microtubules isolated from bovine brain under the s ame conditions (average velocity, about 4.1 mu m s(-1)). These results suggest that plant microtubules have an intrinsic ability to interact with and to be translocated by dynein. It is postulated that microtub ule-based motor proteins, including dynein ATP-ase, are involved in th e functioning of microtubules in plant cells.