Sonic hedgehog (SHH) A protein that has a crucial role in patterning and development of tissues in vertebrates, particularly of the nervous and skeletal systems. It is homologous to Hedgehog protein, which performs a similar function in the fruit fly Drosophila – Hedgehog was so named because mutation of its gene in Drosophila produced flies bearing spiky denticles resembling the spines of a hedgehog.
Sonic hedgehog, named after a video game character, is one of three proteins belonging to the Hedgehog family in vertebrates – the others being Desert hedgehog (DHH) and Indian hedgehog (IHH). It acts as a morphogen, influencing the fate of embryonic cells in the vicinity according to its source and concentration. For example, it is released by the notochord and induces the formation of floor plate cells and motor neurons along the ventral midline of the spinal cord. Patterning of developing limbs is also regulated by SHH.
How to cite this entry: "Sonic hedgehog" A Dictionary of Biology. Elizabeth Martin and Robert Hine. Oxford University Press, 2008. Oxford Reference Online. Oxford University Press. 21 February 2012
