Primary Cilia, Sonic Hedgehog Signaling, and Spinal Cord Development

Abstract

Embryonic spinal cord development requires Sonic hedgehog (Shh) signaling to define ventral motor neuron and interneuron progenitor domains during neural patterning. Shh signaling is inextricably linked to primary cilia, and mutations that disrupt cilia structure and/or function lead to abnormal Shh signaling. The embryonic spinal cord is highly sensitive to perturbations in Shh activity and displays abnormal patterning phenotypes when Shh signaling is up- or downregulated. Mutations in a variety of different cilia genes lead to neural tube patterning phenotypes that provide useful information about the role of different proteins in transducing Shh signals. Here we discuss Shh-dependent spinal cord development and describe what is currently known about the molecular mechanisms regulating Shh signaling in the neural tube.