axon development

Definition

Target type: biologicalprocess

The progression of an axon over time. Covers axonogenesis (de novo generation of an axon) and axon regeneration (regrowth), as well as processes pertaining to the progression of the axon over time (fasciculation and defasciculation). [GOC:dph, GOC:pg, GOC:pr]

Axon development is a fundamental process in the nervous system, whereby a specialized projection, the axon, extends from a neuron to establish connections with other neurons or target cells. This intricate process involves a series of coordinated molecular events, including:

1. **Axon initiation:** This marks the beginning of axon formation, where a specialized region at the neuronal cell body, called the axon initial segment (AIS), emerges. The AIS serves as a critical site for the regulation of axon outgrowth and the generation of action potentials.

2. **Axon guidance:** Once initiated, the axon must navigate through the complex environment of the nervous system to reach its target. Axon guidance cues, both attractive and repulsive, direct the axon along specific pathways. These cues include soluble factors, such as netrins and semaphorins, as well as cell surface molecules, such as Eph receptors and their ligands.

3. **Axon elongation:** The axon continuously extends its length through the polymerization of tubulin subunits into microtubules, which form the cytoskeletal framework of the axon. This elongation process is tightly regulated by a complex interplay of signaling pathways, including the Rho GTPases and the mTOR pathway.

4. **Axon branching:** In many cases, the axon forms branches that enable the neuron to connect with multiple targets. Axon branching is controlled by a variety of factors, including growth factors, such as BDNF, and guidance cues.

5. **Synapse formation:** Once the axon reaches its target, it forms specialized junctions called synapses, where neurotransmitters are released to communicate with the postsynaptic cell. Synapse formation involves a complex series of molecular interactions between the presynaptic axon terminal and the postsynaptic cell.

6. **Axon maturation:** Following synapse formation, the axon undergoes further maturation, including the stabilization of its cytoskeletal structure, the formation of myelin sheaths (in peripheral neurons), and the refinement of its synaptic connections.

These intricate molecular events ensure that axons develop and function correctly, allowing for the transmission of information throughout the nervous system.'
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Proteins (5)

Compounds (289)