First published online December 21, 2007
Development 135, 202e (2008)
© The Company of Biologists Limited
Wnt-Shh neural tube patterning crosstalk
In the developing spinal cord, morphogenetic signals secreted from dorsal
and ventral signalling centres control dorsoventral (DV) patterning. The
Shh/Gli pathway plays a major role in patterning the ventral neural tube but
what restricts its activity to specific domains? On
p. 237, Alvarez-Medina
and colleagues propose that the Wnt canonical pathway fulfils this role. Wnt1
and Wnt3a, which signal through the canonical β-catenin pathway, are
expressed in the dorsal midline region of chick embryos. Their misexpression
along the DV axis by in ovo electroporation, the authors report, expands
dorsal marker gene expression in the developing neural tube, whereas their
inhibition suppresses the dorsal programme and expands ventral gene
expression. These phenotypes, the authors show, depend on the Wnt-controlled
expression of Gli3, which in its repressor form (Gli3R) acts as the main
transcriptional repressor of the Shh/Gli pathway. Together, these observations
suggest that the Wnt canonical pathway indirectly restricts graded Shh/Gli
ventral patterning activity by regulating the dorsal expression of Gli3 to
ensure proper spinal cord patterning.
Related articles in Development:
- Wnt canonical pathway restricts graded Shh/Gli patterning activity through the regulation of Gli3 expression
- Roberto Alvarez-Medina, Jordi Cayuso, Tadashi Okubo, Shinji Takada, and Elisa Martí
Development 2008 135: 237-247.
[Abstract]
[Full Text]
