Virally mediated misexpression of Hoxc-6 in the cervical mesoderm results in spinal nerve truncations

Members of the Hox gene family appear to regulate anterior-posterior (A-P) regionalization in embryos. Genetic manipulation of numerous Hox genes in the developing trunk region of vertebrates results in changes in the morphology of individual vertebrae. We have used virally mediated, targeted misexpression to ectopically express the Hoxc-6 protein in chick embryos. Hoxc-6 has an anterior border of expression at the cervical-thoracic transition in tetrapods. Misexpression of this gene in the cervical mesoderm of chick embryos results in dramatic truncations of the ventral rami of cervical spinal nerves in the infected region. These data point to a role for Hoxc-6 in axon guidance, and suggest that in addition to regulating proliferative rates, Hox gene expression provides positional information utilized in producing domain-specific extracellular signals.