Journal Article

Sonic Hedgehog-Signalling Patterns the Developing Chicken Comb as Revealed by Exploration of the Pea-comb Mutation

Vieaud, Agathe, Gourichon, David, Tixier-Boichard, Michèle, Boije, Henrik, Imsland, Freyja, Hallböök, Finn, Bed’hom, Bertrand, Bruneau, Nicolas, Andersson, Leif, Harun-Or-Rashid, Mohammad, Lee, Yu-Jen

2012

Overview

The genetic basis and mechanisms behind the morphological variation observed throughout the animal kingdom is still relatively unknown. In the present work we have focused on the establishment of the chicken comb-morphology by exploring the Pea-comb mutant. The wild-type single-comb is reduced in size and distorted in the Pea-comb mutant. Pea-comb is formed by a lateral expansion of the central comb anlage into three ridges and is caused by a mutation in SOX5, which induces ectopic expression of the SOX5 transcription factor in mesenchyme under the developing comb. Analysis of differential gene expression identified decreased Sonic hedgehog (SHH) receptor expression in Pea-comb mesenchyme. By experimentally blocking SHH with cyclopamine, the wild-type single-comb was transformed into a Pea-comb-like phenotype. The results show that the patterning of the chicken comb is under the control of SHH and suggest that ectopic SOX5 expression in the Pea-comb change the response of mesenchyme to SHH signalling with altered comb morphogenesis as a result. A role for the mesenchyme during comb morphogenesis is further supported by the recent finding that another comb-mutant (Rose-comb), is caused by ectopic expression of a transcription factor in comb mesenchyme. The present study does not only give knowledge about how the chicken comb is formed, it also adds to our understanding how mutations or genetic polymorphisms may contribute to inherited variations in the human face.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Agricultural and Veterinary Sciences / Agricultural Biotechnology / Agriculture / Analysis / Animals / Biochemistry / Biology / Bioteknologi med applikationer på växter och djur / Cartilage - drug effects / Cartilage - growth & development / Chick Embryo / Chickens / Chickens - genetics / Comb and Wattles - drug effects / Comb and Wattles - embryology / Comb and Wattles - metabolism / Down-Regulation - drug effects / Down-Regulation - genetics / Ectoderm - drug effects / Ectoderm - embryology / Ectoderm - metabolism / Ectopic expression / Extracellular matrix / Female / Gene expression / Gene Expression Regulation, Developmental - drug effects / Genes / Genetic aspects / Genetic Association Studies / Genetic polymorphisms / Genetics / Genetics and Breeding / Genetics and Breeding in Agricultural Sciences / Genetik och förädling / Genetik och förädling inom lantbruksvetenskap / Genotype & phenotype / Hedgehog protein / Hedgehog Proteins - metabolism / Humans / Laboratories / Lantbruksvetenskap och veterinärmedicin / Male / Mesenchyme / Morphogenesis / Morphology / Mutation / Mutation - genetics / Neurosciences / Phenotype / Poultry / Signal Transduction - drug effects / Signaling / SOXD Transcription Factors - metabolism / Staining and Labeling / Transcription (Genetics) / Transcription factors / Veratrum Alkaloids - pharmacology