This award will support collaborative research between Dr. James Bamburg, Colorado State University, and Dr. Dennis Bray, Cell Biophysics Unit, Medical Research Coucil, London. In this project Dr. Bamburg and Dr. Bray will investigate the sites of assembly of actin into the neuronal cortex using fluorescence and electron microscopy. Actin filaments are the major cytoskeletal element of the neuronal growth cone and comprise the core structure of microspikes, pseudopodia which extend from the growth cone and which generate the tension required for directed neurite growth. Drs. Bamburg and Bray plan to identify putative complexes between actin and other proteins in transit to the axonal cortex. The proposed experiments should determine if actin subunits exchange between the filament population in the axon during transport, and if the cortical actin layer of the axon arises from deposition at the growth cone or the shaft. During the course of the project, Dr. Bamburg will prepare proteins for microinjection; Dr. Bray will prepare antibodies against the fluorescent labels. The microinjections studies will be carried out in both laboratories. The proposed studies are well suited for collaboration between these two laboratories. Dr. Bray has been a leader in the development of neuronal culture methods, production of antibodies to neuronal cell proteins, and the application of immunocytochemical methods for other localization of proteins within neurons. Dr. Bamburg has been active in isolation and characterization in vitro of proteins ________ involved in cytoskeletal structures and in regulating assembly of cytoskeletal components.
