IMMUNOFLUORESCENCE DEMONSTRATES THE DISTRIBUTION OF ACTIN, MYOSIN AND INTERMEDIATE FILAMENTS IN CULTURED NEUROBLASTOMA CELLS

Abstract

Monolayers of cultured neuroblastoma cells were examined for immunofluorescent reactivity with antibodies directed against actin, myosin or intermediate filaments. In well spread cells, antibody to intermediate filaments stained an intricate cytoplasmic network which extended as filament bundles into cell processes; in poorly spread or rounded cells, the antibody stained thick juxtanuclear filament bundles. By contrast, antibodies to actin or myosin reacted with microspikes and with axonal growth cones. The different topographical distribution of actin, myosin and intermediate filaments suggests that while actin and myosin may have roles in axon elongation, intermediate filaments may function as an internal cytoskeleton as well as in axoplasmic transport. The different distribution of intermediate filaments in well spread compared with rounded cells suggests that the cell makes its filaments prior to axon development and that the filaments subsequently unwind and migrate into the cell processes to form the axon skeleton.