What animals have the sonic hedgehog gene


The Hedgehog pathway is a signal transduction pathway through which cells can respond to external signals. The signaling pathway is named after its ligand "Hedgehog" (Hh), a signal protein which, as a local morphogen, has an important function in the embryonic development of animals and which appeared very early in evolutionary history. A malfunction in this signaling pathway is fatal in embryos and can lead to cancer in adults. Three hedgehog proteins are currently known in vertebrates (sonic hedgehog, indian hedgehog and desert hedgehog).


The hedgehog signaling pathway is based on proteolysis and is activated when the hedgehog protein hits the receptor Patched binds. This leads to another membrane-bound protein, Smoothened, a signal to the inside of the cell, which the degradation of the regulatory protein Ci (Cubitus interruptus) prevented. Without the action of hedgehog, this becomes a larger protein complex - consisting of the protein Costal, the serine-threonine kinase Fused as well as the inhibitor of Fused - degraded. If Hedgehog is now active and transmits a signal, the protein can Ci are no longer broken down, diffuses into the cell nucleus and regulates gene expression there.


Hedgehog-like genes and 2 homologues too Patched were already in the nematode C. elegans found [1][2] and it has been shown that these genes, as in other animals, play an important role in the development of C. elegans play[1].

In insects, the Hedgehog signaling pathway controls the correct sequence of segmentation and wing formation. In vertebrates, on the other hand, it induces the right-left symmetry and is responsible for the correct formation of limb appendages.


The gene coding for hedgehog in the fruit fly Drosophila melanogaster was among the first genes described as important for development. It was first described by the researchers Christiane Nüsslein-Volhard and Eric F. Wieschaus (both received a Nobel Prize in 1995 “for their fundamental knowledge about the genetic control of early embryo development”[3]), whereby they discovered various mutations through a genetic screen, which influence the embryonic development of Drosophila. [4] The name Hedgehog (Engl.Hedgehog) is due to the "hedgehog-like" appearance of fly larvae, which carried a mutation in the gene for hedgehog.


  1. ab Zugasti O, Rajan J and Kuwabara PE (2005) "The function and expansion of the Patched- and Hedgehog-related homologs in C. elegans" in Genome Research Volume 15, pages 1402-1410. PMID 16204193
  2. Novatchkova M, Wildpaner M, Schweizer F and Eisenhaber F (2005) "PhyloDome - visualization of taxonomic distributions of domains occurring in eukaryote protein sequence sets" in Nucleic Acids Research Volume 33 (Web Server issue): W121-5.PMID 15980439
  3. 1995 Nobel Prize for discovery of the genetic control of early embryonic development
  4. Nusslein-Volhard C and Wieschaus E (1980) "Mutations affecting segment number and polarity in Drosophila" in Nature Volume 287, pages 795-801. PMID 6776413

See also


  • B. Alberts et al: Molecular Biology of the Cell. 2002.

Category: Signal Transduction