Sea urchin eggs will be used as a system to examine the cellular mechanisms that regulate the actin cytoskeleton. Following fertilization, the egg undergoes definable changes in its actin cytoskeleton in almost perfect synchrony with a series of defined metabolic and ionic changes. The proposed experiments wil examine the in vitro effects of three calcium-sensitive actin binding proteins (egg spectrin, egg 95K, and egg 50K) on actin filament assembly and structure. Polyclonal antibodies monospecific for these proteins will be generated and used for indirect immunofluorescence to examine the spatio-temporal relationship between the actin binding proteins and actin within oocytes, eggs, and embryos. The antibodies will also be used to examine tissue specific expression of the actin binding proteins. If necessary, monoclonal antibodies will be generated to pursue this work. The long term goals of this project are to establish insight into how cells are able to maintain and modulate their actin cytoskeletons with such amazing precision. This is fundamentally important, because the microfilament systems of virtually all eucaryotic cell types are crucial to the proper cytoplasmic and membranous organization (and hence function) of the cells.
