Dev Biol 2003 May 15;2572:343-55. doi: 10.1016/s0012-1606(03)00065-4.

The amino-terminal region of Gli3 antagonizes the Shh response and acts in dorsoventral fate specification in the developing spinal cord.

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A concentration gradient of Shh is thought to pattern the ventral neural tube, and these ventral cell types are absent in shh-/- mice. Based on in vitro and genetic studies, the zinc finger-containing transcription factors Gli 1, 2, and 3 are mediators of the Shh intracellular response. The floorplate and adjacent cell types are absent in gli1-/-;gli2-/- mice, but part of the Shh-/- phenotype in the neural tube is alleviated in the Shh-/-;gli3-/- double mutant. This is consistent with the predicted role of Gli3 as a repressor of the Shh response. Gli3 repressor activity is blocked by Shh. In order to test the role of the repressor form of Gli3 in the neural tube, a truncated version of Gli3 (Gli3R*) was designed to mimic a Pallister Hall allele. Gli3R* acts as a constitutive repressor independent of Shh signaling. Misexpression of Gli3R* in the chick neural tube caused a ventral expansion of class-I, dorsal progenitor proteins and a loss of class-II, ventral progenitor proteins consistent with expected activity as a repressor of the Shh response. Activation of the BMP response is sufficient to maintain gli3 expression in neural plate explants, which might be a mechanism by which BMPs antagonize the Shh response.

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Species referenced: Xenopus
Genes referenced: bmp4 dbx1 dbx2 gli1 gli2 gli3 irx3 msx1 msx2 nkx2-2 nkx6-1 pax6 pax7 shh
GO keywords: smoothened signaling pathway [+]

???displayArticle.omims??? PALLISTER-HALL SYNDROME; PHS