Neuronal fibrillar proteins and axoplasmic transport.

Proteins synthesized in ganglion cells of the rabbit retina were labeled with [3H]leucine or [14C]glycine injected into the vitreous. The labeled proteins that were transported into the optic nerve and tract were dissolved and analyzed by polyacrylamide gel electrophoresis. Under simple electrophoretic conditions the incorporated label appeared to be broadly distributed over the bands of axonal proteins but with a discontinuous buffer system where higher resolution was achieved, the prominent stained bands of actin, tubulin and neurofilament did not coincide with any peaks of radioactivity. Thus the specific activity of those proteins is lower than that of other migrating proteins and it is concluded that these proteins do not move in toto with axoplasmic flow.