Intracellular structures controlling the morphological differentiation of nerve cells

Microtubules and microfilaments have been studied in neuroblastoma and sympathetic cells in culture by means of a high-resolution technique of immunofluorescence microscopy employing monospecific antibodies raised against purified tubulin and actin. A marked intracellular redistribution of microtubules and microfilaments occurs during in vitro induced axonal extension. In both cell types microtubules channel into outgrowing axons while microfilaments are predominantly associated with highly motile protrusions of the cell surface notably at growth cones. An important role of cytoskeletal and contractile structures in controlling and maintaining the specific neuronal shape is proposed for in vitro growing cells and extended also to nerve cells differentiating in vivo.