AXOTOMY-INDUCED REGULATION OF C-JUN EXPRESSION IN REGENERATING RAT RETINAL GANGLION-CELLS

Antibodies to c-Jun, JunD, JunB, c-Fos, FosB and Krox-24 proteins were used to examine the expression of these transcription factors in iden tified adult rat retinal ganglion cells with regenerating axons in a p eripheral nerve graft. First, expression in ganglion cells 1 month aft er graft placement was compared to expression in these neurons 5 to 6 months after grafting. Whereas strong c-Jun expression was seen in mos t ganglion cells one month after grafting, most 5- to 6-month ganglion cells showed only basal expression. The maintained nucleolar expressi on of FosB in both ganglion cell groups was the only other transcripti on factor seen. Second, transcription factor expression was examined i n these short- and long-term regenerating neurons after a second axoto my caused by graft transection and compared to the effects of a single axotomy on expression in non-regenerating ganglion cells. Only c-Jun was re-expressed in the regenerating ganglion cells after re-axotomy.