Target regulation of protein biosynthesis in retinal ganglion cells during regeneration of the goldfish visual system.

Transected ganglion cells of the goldfish retina demonstrate a marked increase in protein biosynthesis as their axons regrow into a primary target tissue, the optic tectum. In order to examine what role the target tissue may play in regulating the pattern of neuronal protein biosynthesis, the tectum is removed at the time of axotomy. By 10 days after surgery, the production of specific polypeptides including the structural proteins, tubulin and actin, are not affected by tectal ablation. However, during a later phase of regeneration when axons would normally begin to re-connect with the tectum, the appearance of a radiolabeled polypeptide of 300 kDaltons is blocked by tectal ablation. These data suggest that ganglion cells are regulated by target tissues late in the regenerative process perhaps by contact between axons and cells of the tectum.