Acquisition of granule neuron precursor identity is a critical determinant of progenitor cell competence to form Shh-induced medulloblastoma.

Whether the brain tumor medulloblastoma originates from stem cells or restricted progenitor cells is unclear. To investigate this, we activated oncogenic Hedgehog (Hh) signaling in multipotent and lineage-restricted central nervous system (CNS) progenitors. We observed that normal unipotent cerebellar granule neuron precursors (CGNPs) derive from hGFAP(+) and Olig2(+) rhombic lip progenitors.

Molecular control of spinal accessory motor neuron/axon development in the mouse spinal cord.

Within the developing vertebrate spinal cord, motor neuron subtypes are distinguished by the settling positions of their cell bodies, patterns of gene expression, and the paths their axons follow to exit the CNS. The inclusive set of cues required to guide a given motor axon subtype from cell body to target has yet to be identified, in any species. This is attributable, in part, to the unavailability of markers that demarcate the complete trajectory followed by a specific class of spinal motor axons.