Transcriptional control of the terminal fate of monoaminergic neurons

Monoaminergic neurons are critical functional components of all nervous systems across phylogeny. The terminally differentiated state of individual types of monoaminergic neurons is defined by the coordinated expression of a battery of genes that instructs the synthesis and transport of specific monoamines, such as serotonin or dopamine. Dysfunction or deregulation of several of these enzymes and transporter system has been proposed to be the underlying basis of several pathological conditions. We review here the state of knowledge of the nature of the transcriptional regulatory programs that control the expression of what we term monoaminergic gene batteries (enzymes and transporters for specific monoamines) and thereby define the terminally differentiated state of monoaminergic neurons. We review several case studies in vertebrate and invertebrate model systems and propose that the coordinated expression of the genes that define individual monoaminergic cell types may be brought about by transcriptional coregulatory strategies.