Changes in intracellular organization of tubulin and actin in N-18 neuroblastoma cells during the process of axon extension induced by serum deprivation.

Specific antibodies against actin and tubulin have been used to follow the distribution and organization of actin and tubulin containing structures in N-18 neuroblastoma cells induced to sprout axons. Immunofluorescence microscopy shows that during the time of axonal sprouting microtubules converge into growing processes forming dense bundles in which individual microtubules cannot be resolved. In the growth cone where individual fluorescent fibers can again be distinguished microtubules seem to be excluded from the very margin. Actin is predominantly located at the cell periphery both in cell bodies and in cell processes. It appears to be present in areas of high surface motility and is especially abundant at the tip of the growth cone.