AP-1 MEDIATES TRANSSYNAPTIC INDUCTION OF TYROSINE-HYDROXYLASE GENE-EXPRESSION IN ADRENAL-MEDULLA BUT NOT IN SUPERIOR CERVICAL-GANGLIA

Reserpine treatment leads to a rapid trans-synaptic increase of the ty rosine hydroxylase (TH) gene transcription rate and mRNA levels in cat echolaminergic tissues including the adrenal medulla (AM) and the supe rior cervical ganglia (SCG), In the AM, the formation of a specific pr otein complex with the TPA-responsive element located in the proximal region of the TH gene was enhanced between 30 min and 8 hr following t he injection, This complex appears to contain a member of the Fos fami ly and an antigenically related Jun protein, Moreover, the prolonged a nd enhanced expression of the c-Fos protein in the AM and its phosphor ylation are likely to contribute to the increased TH transcription fol lowing reserpine treatment, Most strikingly, in the SCG, the transsyna ptic induction of TH transcription is transduced by totally different mechanisms, since no AP-1 complex and only minute amounts of c-Fos imm unoreactivity were detected, Our study provides the first demonstratio n that, following the same stimulus, the induced expression of a singl e gene is mediated by different cis- and trans-acting factors in two d istinct tissues sharing the same embryonic origin. (C) 1997 Wiley-Liss , Inc.