Development of the mammalian axial skeleton requires signaling through the Gαi subfamily of heterotrimeric G proteins.

Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health/Department of Health and Human Services, Durham, NC 27709.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 12/2012; 109(52). DOI: 10.1073/pnas.1219810110
Source: PubMed

ABSTRACT 129/SvEv mice with a loss-of-function mutation in the heterotrimeric G protein α-subunit gene Gnai3 have fusions of ribs and lumbar vertebrae, indicating a requirement for Gα(i) (the "inhibitory" class of α-subunits) in somite derivatives. Mice with mutations of Gnai1 or Gnai2 have neither defect, but loss of both Gnai3 and one of the other two genes increases the number and severity of rib fusions without affecting the lumbar fusions. No myotome defects are observed in Gnai3/Gnai1 double-mutant embryos, and crosses with a conditional allele of Gnai2 indicate that Gα(i) is specifically required in cartilage precursors. Penetrance and expressivity of the rib fusion phenotype is altered in mice with a mixed C57BL/6 × 129/SvEv genetic background. These phenotypes reveal a previously unknown role for G protein-coupled signaling pathways in development of the axial skeleton.

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