Microtubules are intracellular polymers that are required for several vital processes in eukaryotic cells including mitosis, intracellular transport and the maintenance of asymetric cell shape. The goal of the research in this lab is to elucidate the mechanism(s) by which microtubules contribute to these diverse phenomena. Current work focuses on understanding the assembly and disassembly behavior of microtubules in living cells. To analyze microtubule behavior in living cells, we have prepared fluorescent and caged fluorescent analogs of tubulin, the subunit protein of the microtubules. These probes are micro-injected into living cells and the dynamic behavior of the resulting fluorescent microtubules is followed using fluorescence microscopy and digital recording techniques. Using these techniques, we have directly observed the dynamic changes in microtubules as cells progress through the mitotic cycle and demonstrated that the dynamic behavior of interphase microtubules is cell type specific. Future research will examine the regulation of microtubule dynamics throughout the cell cycle and the contribution of microtubule assembly and disassembly behavior to chromosome motion during mitosis. In addition, we have recently demonstrated that the dynamic behavior of interphase microtubules is cell type specific. Molecules which interact with microtubules to generate both the distinct microtubule behavior and the specific arrangement of microtubules in diverse cells throughout development will also be determined.