The authors are in the Department of Molecular Biology,
Genentech Inc., 1 DNA Way, South San Francisco,
California 94080, USA. ar@gene.com
The diffusible signal Sonic Hedgehog (Shh) controls cell type specification
in the ventral spinal cord. Litingtung and Chiang now show that some defects
due to the lack of Shh are rescued by deleting the transcription factor Gli3,
suggesting that Shh works by inactivating Gli3.
