Sonic hedgehog functions to induce floor plate in early stages, and spinal motor neurons
and midbrain dopaminergic neurons in later stages of development. Here, we investigated
the effects of sonic hedgehog on tyrosine hydroxylase expression in three cell lines that
correspond to different stages of neural development. Sonic hedgehog increased the
tyrosine hydroxylase gene expression in pluripotent P19 cells but repressed it in tyrosine
hydroxylase-producing PC12 cells. Promoter analysis in mouse neural stem cells indicated …