Transient Agonism of the Sonic Hedgehog Pathway Triggers a Permanent Transition of Skin Appendage Fate in the Chicken Embryo

May 2023 in “ Science Advances ”

Rory L. Cooper, Michel C. Milinkovitch

sonic hedgehog pathway Shh pathway skin appendages RNA sequencing gene expression

Studysummary In this study, transiently activating the sonic hedgehog signaling pathway in chickens transformed reticulate scales on the feet into feathers comparable to body feathers, without ongoing treatment, suggesting this pathway affects the diversity of bird skin appendages. Our plain-language summary of this paper — not a Tressless recommendation.

The study explores the impact of transient activation of the sonic hedgehog (Shh) pathway on skin appendage fate in chicken embryos, demonstrating that a single injection of a Shh pathway agonist (SAG) at embryonic day 11 can permanently transform scales into feathers. This transformation was observed in 9 out of 20 embryos, with ectopic feathers developing similarly to normal feathers and persisting into adulthood. RNA sequencing confirmed the up-regulation of Shh pathway genes, indicating that this pathway plays a crucial role in the transformation. The findings suggest that variations in Shh signaling may contribute to the diversity of bird skin appendages.

View this study on science.org →

Discuss this study in the Community →

Research cited in this study

4 / 4 results

research Feather Arrays Are Patterned by Interacting Signaling and Cell Density Waves

133 citations , February 2019 in “PLoS Biology”

This research found that feather pattern formation in birds is regulated by a mechanochemical system involving fibroblast growth factor and bone morphogenetic protein signaling, which is altered in the flightless emu and ostrich.

Comprehensive Molecular and Cellular Studies Suggest Avian Scutate Scales Are Secondarily Derived from Feathers, and More Distant from Reptilian Scales

research Comprehensive Molecular and Cellular Studies Suggest Avian Scutate Scales Are Secondarily Derived from Feathers, and More Distant from Reptilian Scales

38 citations , November 2018 in “Scientific Reports”

This study suggests that chicken and alligator scales evolved independently through convergent evolution rather than sharing a common origin with avian feathers.

research BMP2 And BMP7 Play Antagonistic Roles In Feather Induction

88 citations , July 2008 in “Development”

This study shows that BMP2 and BMP7 play complex, necessary roles in feather development by regulating dermal condensation formation, with BMP7 acting early as a chemoattractant and BMP2 halting cell migration.

research The Secret Life of the Hair Follicle

745 citations , February 1992 in “Trends in genetics”

This article describes the potential role of various growth factors and molecules in regulating mammalian hair follicle development but does not present new experimental results.