C-FOS AS A TRANSCRIPTION FACTOR - A STRESSFUL (RE)VIEW FROM A FUNCTIONAL MAP

This article summarizes the achievements that have been accumulated ab out the role of c-Fos as a transcription factor and as a functional ma rket of activated neurons. Since its discovery, more than a decade ago , as an inducible immediate-early gene encoding a transcription factor , or third messenger, involved in stimulus-transcription coupling and mediation of extracellular signals to long-term changes in cellular ph enotype, c-fos became the most widely used powerful tool to delineate individual neurons as well as extended circuitries that ale responsive to wide variety of external stimuli. There still remain uncertainties as to how general is the c-fos induction in the central neurons, and whether the threshold of c-fos induction is comparable along a certain neuronal circuit. The major limitation of this technology is that c-f os does not mark cells with a net inhibitory synaptic or transcription al drive, and c-fos induction, as a generic marker of trans-synaptic a ctivation, does not provide evidence for transcriptional activation of specific target genes in a certain cell type of interest. The first p art of the review focuses on recent functional data on c-fos as transc ription factor, while the second part discusses c-fos as a cellular ma rker of transcriptional activity in the stress-related circuitry. (C) 1998 Elsevier Science Ltd. All rights reserved.