First published online July 27, 2007
Development 134, 1603e (2007)
© The Company of Biologists Limited
Cracking the rib cage code
Patterning of the rib cage is complex, not least because it derives from
two different tissues - the somitic mesoderm (which forms the vertebrae and
ribs) and the lateral plate mesoderm (which forms the sternum). On
p. 2981, Deneen
Wellik and colleagues shed light on the `Hox code' that orchestrates
development of the thoracic skeleton. They made mutant mice lacking whole
groups of paralogous Hox genes - Hox5, Hox6 and Hox9 - which
had dramatic effects on rib cage morphology. Surprisingly, the phenotypes do
not fit with the simplest version of the model of `posterior prevalence', in
which posterior groups of Hox genes are functionally dominant over the
next-most anterior group. Consistent with Hox genes in other tissues, the
phenotypes in the somite-derived skeleton do have consistent colinearity - the
genomic distribution of the genes is reflected in their spatial and temporal
expression and function during development. However, no such colinearity is
seen in the sternum. The authors conclude that Hox patterning of the thoracic
skeleton occurs through different mechanisms depending on the mesodermal
tissue from which it derives.
Related articles in Development:
- Hox patterning of the vertebrate rib cage
- Daniel C. McIntyre, Sabita Rakshit, Alisha R. Yallowitz, Luke Loken, Lucie Jeannotte, Mario R. Capecchi, and Deneen M. Wellik
Development 2007 134: 2981-2989.
[Abstract]
[Full Text]
