First published online May 11, 2006
Development 133, 1105e (2006)
© The Company of Biologists Limited
Pbx genes extend a limb
For years, developmental biologists have been trying to understand how
positional information controls the development of vertebrate limbs. New
insights into this three-dimensional puzzle are provided by Capellini and
co-workers on p.
2263, who reveal that the homeoproteins Pbx1/Pbx2 regulate distal
limb patterning in mice. Pbx1 is essential for proximal limb development but
Pbx2-deficient embryos have normal limbs. The researchers now show that
compound Pbx1–/–, Pbx2+/– mutant
embryos have severe distal limb abnormalities–the fibula and most of the
digits are lost in the hindlimb–in addition to exacerbated proximal
abnormalities. This distal phenotype resembles that seen in embryos that lack
sonic hedgehog (Shh), and indeed, the loss of skeletal elements in mutant
hindlimbs is mediated by the absence of Shh. This deficit is preceded by a
severe perturbation of Hox gene expression. The researchers conclude,
therefore, that Pbx1/Pbx2 regulate vertebrate distal limb patterning partly by
controlling the spatial expression of Hox genes and Shh expression.
Related articles in Development:
- Pbx1/Pbx2 requirement for distal limb patterning is mediated by the hierarchical control of Hox gene spatial distribution and Shh expression
- Terence D. Capellini, Giuseppina Di Giacomo, Valentina Salsi, Andrea Brendolan, Elisabetta Ferretti, Deepak Srivastava, Vincenzo Zappavigna, and Licia Selleri
Development 2006 133: 2263-2273.
[Abstract]
[Full Text]
