Several forms of intracellular transport, or movement, which are essential for normal cell growth and function depend on linear intracellular elements called microtubules. One example is chromosome movement during cell division; another is the transporrt of neurotransmitter-containing vesicles from one end of a nerve cell to the other. Two molecules have been described which serve as "molecular motors;" i.e., which are able to convert the chemical energy of ATP into mechanical force associated with the microtubules. One is called kinesin, and the other is called dynein. The objective of this proposal is to test the idea that an unusual form of dynein found in sea urchin eggs is the motor for microtubule-associated motility in this system. The specific goals of the project are: first, to obtain specific antibodies against the sea urchin egg dynein and use these to localize and quantitate dynein during embryonic development; then, to obtain a DNA clone for the sea urchin dynein using recombinant DNA techniques, and to use this clone as a probe to determine whether there are multiple, and possibly even tissue and stage-specific dynein genes. The anticipated results will add new and important information regarding the molecular basis of microtubule-based motility.