Chapter 17 Immediate early genes (IEGs) encoding for inducible transcription factors (ITFs) and neuropeptides in the nervous system: functional network for long-term plasticity and pain

This chapter discusses the immediate early genes ( IEGs) encoding for inducible transcription factors ( ITFs) and neuropeptides in the nervous system: functional network for long-term plasticity and pain Lasting biochemical and functional changes in the nervous system following physiological or pathophysiological stimulation often involve mechanisms at the level of gene expression. Among the earliest steps of these processes is the rapid induction of immediate early genes (IEGs). In vitro studies on neuronal and non-neuronal cells have established that growth factors, hormones, or peptides induce IEGs. Among the best studied, IEGs are those of fos (c-fos, fosB, fra-1, fra-2), jun (c-jun, junB, junD) and krox (krox-20, krox-24) families. These IEGs encode for inducible transcription factors (ITFs), a group of nuclear proteins that bind to regulatory DNA promoter, and enhancer sites and control the transcription of numerous target or effector genes. This sequence of events turned out to be a universal master switch of stimulation-transcription coupling. Apart from ITFs, IEGs also encode for secretory proteins, enzymes, or membrane receptors.. This article reviews the findings on ITFs in the nervous system, and a particular emphasis is on their relationship with neuropeptides, contributing to the processes of neuronal plasticity during pain and nerve fiber damage.