central nervous system projection neuron axonogenesis

Definition

Target type: biologicalprocess

Generation of a long process of a CNS neuron, that carries efferent (outgoing) action potentials from the cell body towards target cells in a different central nervous system region. [GO_REF:0000021, GOC:cls, GOC:dgh, GOC:dph, GOC:jid]

Central nervous system (CNS) projection neuron axonogenesis is a complex and highly regulated process that involves the extension of axons from neuronal cell bodies to their target regions throughout the nervous system. This process is essential for establishing functional neuronal circuits and is critical for proper brain development and function.

Axonogenesis begins with the formation of a growth cone, a specialized structure at the tip of the extending axon. The growth cone is highly motile and is responsible for sensing and navigating the extracellular environment to find its appropriate target. The growth cone is composed of a variety of cellular components, including microtubules, actin filaments, and membrane receptors, which work together to mediate its movement and guidance.

The growth cone is guided by a variety of cues, both attractive and repulsive, that are present in the extracellular environment. These cues can be either soluble factors, such as neurotrophins and guidance molecules, or cell-surface proteins, such as cell adhesion molecules. The growth cone interacts with these cues through specific receptors located on its surface, which trigger intracellular signaling pathways that ultimately determine the direction of growth.

One key aspect of axonogenesis is the process of pathfinding, where the axon navigates through the complex environment of the developing CNS to reach its target. This process involves a combination of mechanisms, including:

- **Chemoattraction:** The growth cone is attracted to gradients of attractive cues, such as neurotrophins and other guidance molecules, that are released from target cells.
- **Chemorepulsion:** The growth cone is repelled from gradients of repulsive cues, such as semaphorins and ephrins, which prevent axons from growing in inappropriate directions.
- **Contact guidance:** The growth cone can also follow physical cues, such as cell-surface proteins and extracellular matrix components, that provide a substrate for its movement.

As the axon grows, it undergoes a process of elongation and differentiation. The axon elongates by adding new cytoplasm and microtubules at its tip. At the same time, the axon also undergoes structural and functional changes that are necessary for its specialized role in neuronal signaling. This includes the formation of synapses, the junctions between neurons where communication takes place.

The entire process of axonogenesis is tightly regulated by a complex network of genes and signaling pathways. These pathways involve various transcription factors, kinases, and signaling molecules that control the expression and activity of genes that are involved in axon growth, guidance, and differentiation. Disruptions in these pathways can lead to developmental defects in the nervous system, such as neurological disorders and cognitive impairments.

In summary, axonogenesis is a highly dynamic and complex process that is essential for the development and function of the CNS. It involves a series of coordinated steps, including growth cone formation, pathfinding, elongation, and differentiation, which are controlled by a complex network of genes and signaling pathways.'
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Proteins (6)

Compounds (321)