The long-term goal of this project is to determine the mechanisms by which organelles move through cells. It is important to understand these mechanisms because such physiologically important phenomena as axonal transport and enzyme and hormonal secretion are forms of organellar translocation. Combined genetic, morphological, and biochemical approaches will be used to study organellar translocation in the filamentous fungus Aspergillus nidulans, which is uniquely suited for such studies. Mutations have been isolated in the Alpha- and Beta-tubulin genes and in seven other genes that are essential to organellar translocation. To identify the products of these genes, the genes will be cloned by complementation and sequenced. Antigens will be produced from the cloned genes and will be used to raise antibodies. These antibodies will be used to identify and purify the products of the organellar translocation genes. New organellar translocation mutants will be isolated as revertants of existing organellar translocation mutants and among randomly isolated conditionally lethal mutants. The newly isolated mutants will be tested for allelism to existing mutants and to each other and will be mapped to locus. These mutants will be characterized morphologically at the light microscopic level to determine if each mutation specifically blocks one form of organellar translocation, such as nuclear movement, or if it has more general effects on organellar translocation or microtubule function. They will also be examined by fluorescence microscopy to determine if they affect microtubule or microfilament assembly or distribution.