Fig. 8.

Summary of Hedgehog regulation and loss-of-function studies. A: Effects on spinal cord development after blocking Hedgehog signaling. The nkx6.2 expression is lost, and dbx1a/1b expression expands ventrally. The dorsal boundaries of dbx1a/1b and msxc expression are unaffected. In addition, postmitotic neurons from the Dbx domain are expanded. B: Effects on spinal cord development after dbx1a and dbx1b are knocked down. In morphants, nkx6.2 expression expands dorsally while the ventral limit of msxc expression is unaffected. Also, postmitotic neurons produced from the Dbx domain are reduced in morphants.