REGULATION OF NEURITE OUTGROWTH AND SNAP-25 GENE-EXPRESSION BY THE BRN-3A TRANSCRIPTION FACTOR

SNAP-25 is a presynaptic nerve terminal protein which is also essentia l for the process of neurite outgrowth in vivo and in vitro. However t he processes regulating its expression have not been characterized pre viously. We show that the gene encoding this protein, SNAP, is strongl y activated by the Brn-3a POU (Pit-Oct-Unc) family transcription facto r. Expression of both Brn-3a and SNAP-25 increases when ND7 neuronal c ells are induced to extend neurite processes by serum removal. Inhibit ion of Brn-3a expression in these cells inhibits SNAP-25 expression an d abolishes the neurite outgrowth that normally occurs in response to serum removal. These results identify Brn-3a as the first transcriptio n factor having a role in process outgrowth in neuronal cells acting, at least in part, via the activation of SNAP-25 gene expression.