First published online December 7, 2008
Development 136, 13602e (2009)
© The Company of Biologists Limited
Facing brain's role in craniofacial patterning
Evolutionary changes in brain organisation may partly explain why different
species have different faces, suggest Diane Hu and Ralph Marcucio, who have
been studying upper jaw development (see
p. 107). The growth of
this part of the facial skeleton, which is formed from neural crest-derived
cells, is controlled by Sonic hedgehog (SHH) signals from the frontonasal
ectodermal zone (FEZ). Variations in the FEZ (the establishment of which
requires Shh expression in the developing forebrain) underlie the
divergent facial morphogenesis of birds and mammals. The researchers now
report that activation of the SHH pathway in chick brains superimposes a
mammalian-like morphology onto the chick's upper jaw and splits its single FEZ
into right and left domains that resemble those of mice. The expression of
several other signals (including Fgf8) in the brain and in the nasal
pit is also altered in the SHH-treated chicks, note Hu and Marcucio. Thus,
they suggest, the brain establishes multiple signalling centres within the
developing upper jaw that regulate craniofacial morphogenesis.

CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati
Twitter What's this?
Related articles in Development:
- A SHH-responsive signaling center in the forebrain regulates craniofacial morphogenesis via the facial ectoderm
- Diane Hu and Ralph S. Marcucio
Development 2009 136: 107-116.
[Abstract]
[Full Text]