Genes and Neurons

Abstract

Genes encode proteins that are critical for the development and regulation of neural circuits involved in various aspects of brain function such as emotion, thought, learning, and neurological disease. We would like to understand the manner in which proteins responsible for neuronal activities are related to mental processes or brain diseases. Molecular genetics provides the means to determine the genes involved in a particular function of the brain. The human genome project has revealed that a human cell has approximately 30,000–60,000 genes. Neurons differ from other types of cells because they express a set of genes that is specific to them. Neurons are estimated to express ∼ 40% of their total genes, some of which are also expressed in other types of cells. Neuron-specific genes encode neuropeptides, enzymes involved in the synthesis of neurotransmitters (NT), ion channels and receptors, synaptic proteins, and neurotrophic receptors. However, genes expressed in other cell types, such as those encoding protein kinases, cytoskeletal proteins, growth factors, etc., collaborate with neuron-specific genes and are thus involved in neuron-specific behavior such as axon guidance, synaptic plasticity, and neuronal cell death. In this chapter, we examine the basic structure of neurons and discuss genes and proteins that play a key role in neuronal functions. Although complex functions of the brain are determined by the pattern of neuronal connectivity and probably by the number of neurons, it is important to understand the molecular machinery of neurons and synapses given that genetic defects are known to cause many neurological disorders. In addition, remarkable progress has been made to develop drugs that target specific molecules or genes involved in neuronal functions.