Nerve growth factor induces the proto-oncogene c-jun in PC12 cells

Nerve growth factor (NGF) induces the rapid but transient expression of two transcripts with homology to the proto-oncogene c-jun (AP-1) in PC12 cells. The c-jun transcripts increase within 15 min after NGF addition, peak at 1 h, and decline to basal level by 4 h. Actinomycin D inhibits the increase, and cycloheximide prevents the decrease of c-jun mRNA. Cyclic AMP induces a similar transient rise in c-jun transcripts in PC12 cells. The human melanoma cell line A875 that also expresses the NGF receptor expresses c-jun RNA constitutively, and the level of c-jun RNA is not affected significantly by NGF. NGF does not alter the RNA level of transcription factor SP-1 in PC12 cells. The results suggest that activation of the putative transcription factor c-jun is one of the early cellular responses of PC12 cells to NGF and that c-jun mRNA expression is dependent on cellular transcription and regulated by stabilization of c-jun mRNA.