The invention also provides a method for modulating {TAIL ~ proliferation} or {HEAD ~ differentiation} of neuronal cells comprising contacting the cells with a hedgehog polypeptide 
The invention also provides a method for modulating { TAIL ~ proliferation } or { HEAD ~ differentiation } of neuronal cells comprising contacting the cells with a hedgehog polypeptide
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH