Development and Differentiation of Autonomic Neurons

Publisher Summary This chapter focuses primarily on the transcriptional regulatory code underlying the development and neurotransmitter identity determination of the autonomic nervous system (ANS). The enteric system regulates peristalsis of the gut wall and modulates the activity of the secretary glands. During the last decade, exciting progress has been made with regard to the molecular mechanisms underlying the development of the ANS. Various transcription factors are thought to trigger a regulatory cascade by inducing the expression of downstream transcription factors, which eventually activate or repress the final target genes. A closely related transcription factor Phox2b is also induced by bone morphogenic protein (BMP) independently of Mash1 and is another essential regulator of noradrenergic neuron development. Mash1, a basic helix-loop-helix (bHLH) protein, is the first transcription factor shown to be essential for development of the ANS. Phox2a and Phox2b are two closely related homeodomain transcription factors that are expressed in virtually all neurons that transiently or permanently express the noradrenergic neurotransmitter phenotype.