The expression of the c-src+ proto-oncogene mRNA in foetal striatal tissue grafts

We have studied by in situ hybridization the mRNA expression of the pp60c-src proto-oncogene in grafts of foetal striatal neurons implanted into the ibotenic acid lesioned adult rat neostriatum. Animals were studied at 5, 10, 15, 30 days and 4 months after transplantation. Using 35S-labelled specific oligonucleotide probes, high levels of mRNA for pp60c-src+ but not pp60c-src- were found in the normal embryonic striatum and in striatal grafts up to 1 month after implantation; no hybridization signal was obtained in the normal adult striatum or in 4-month old grafts. The data suggest that pp60c-src+ is highly expressed in developing, but not mature, neurons and may play a fundamental role in the maturation and differentiation of grafted embryonic striatal neurons.