Morphogen

Morphogen is a substance whose non-uniform distribution governs the pattern of tissue development in the process of morphogenesis or pattern formation. The concept of morphogen was introduced by Alan Turing in his work on reaction-diffusion systems, and later developed by Lewis Wolpert in his French flag model.

Definition

A morphogen is a signaling molecule that acts directly on cells (not through serial induction) to produce specific cellular responses dependent on morphogen concentration. Morphogens are usually produced by source cells and form a concentration gradient across a developing tissue. The cells in the developing tissue are exposed to different concentrations of morphogen, which then activate different gene expression programs to specify cell fate.

Examples

Examples of morphogens include BMPs, Dpp, Shh, Wg, and RA. These morphogens act in various developmental processes such as limb development, neural tube patterning, and organogenesis.

Mechanisms

Morphogens work by activating transcription factors, which then regulate the expression of target genes. The concentration of the morphogen determines the level of transcription factor activation, and thus the specific gene expression program that is initiated.

See also

• Pattern formation
• Reaction–diffusion system
• French flag model
• Bone morphogenetic protein
• Decapentaplegic
• Sonic hedgehog
• Wingless
• Retinoic acid

Morphogen

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  Drosophila melanogaster laboratory culture vial