CHRONOLOGICAL EXPRESSION AND ITS SIGNIFICANCE OF C-JUN AND C-FOS MESSENGER-RNA IN RAT-BRAIN

We investigated the expression of c-jun and c-fos proto-oncogenes and their distribution in the brain of newborn to adult rats to determine the relationship between protooncogene expression and brain developmen t, by the reverse transcription-polymerase chain rection (RT-PCR) meth od, in situ hybridization and immunohistochemistry. In the RT-PCR anal ysis, the cDNA fragments of c-jun and c-fos were amplified with expect ed-sizes, and the expression levels were fixed through all ages examin ed. The in situ hybridization showed that the expression of c-jun and c-fos mRNA was located at the cytoplasm of most neurons and some glial cells of the entire portions of the cerebrum, brainstem and cerebellu m until 300 days after birth. c-Jun protein immunoreactivity was detec ted in the nucleus of neurons which demonstrated a positive signal by in situ hybridization. Our results suggest that even after neuroblasts differentiate to mature neurons, c-jun and c-fos genes may have a rol e in the preservation of the neuronal function of the rat central nerv ous system.