Fos/Jun in Brain Function
This chapter focuses on the few emerging aspects of the functional significance of early response genes of the leucine zipper class in brain function. An important step required to link c-fos induction to neuronal function is the identification of targets for the gene transactivation elicited by the products of the immediate early genes. In addition to the prodynorphin gene, two other potential target genes for transactivation by Fos-Jun in the spinal cord are the proenkephalin and the protachykinin genes. Since the process of neuronal cell death requires new protein synthesis, the search for Fos/Jun target genes, the so-called "death genes, " is in progress in many laboratories. Several strategies have been used for the identification of putative target genes. The chapter concludes that c-fos induction in external laminae of the dorsal horn tends to be intense, short lasting, and possibly related to relatively restricted and tightly controlled transcriptional modifications.