A molecule that regulates the first steps of bone repair in mice is reported in a study in the December 2006 issue of Nature Genetics. The molecule, bone morphogenetic protein 2 (BMP2), was long known to be part of a family of proteins that can promote bone growth, but this is the first study to establish one of the BMP proteins as absolutely required for the natural regenerative response in mice.
Vicki Rosen and colleagues deleted the gene encoding BMP2 specifically in developing limbs in mice. While there were no abnormalities observed at birth, by 13 weeks of age all of the mice examined had reduced bone mineral density and spontaneous forearm fractures. Moreover, none of the fractures showed any sign of the normal healing response, despite the presence of progenitor cells at the site of fracture that are the precursors to the bone-generating process. These progenitor cells, which express the receptor for BMP2, failed to differentiate in the BMP2-deficient limbs.
Vicki Rosen (Harvard University, Boston, MA, USA)
Abstract available online.
(C) Nature Genetics press release.
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