The fully linked HTML version of this article has now been published.
Development ePress online publication date 28 Nov 2007
doi: 10.1242/dev.009266
Research article
Wnt3a/
-catenin signaling controls posterior body development by coordinating mesoderm formation and segmentation
William C. Dunty, Jr,
Kristin K. Biris,
Ravindra B. Chalamalasetty,
Makoto M. Taketo,
Mark Lewandoski,
and
Terry P. Yamaguchi*
* Author for correspondence (e-mail: tyamaguchi{at}ncifcrf.gov)
Somitogenesis is thought to be controlled by a segmentation clock, which consists of molecular oscillators in the Wnt3a, Fgf8 and Notch pathways. Using conditional alleles of Ctnnb1 (
-catenin), we show that the canonical Wnt3a/-catenin pathway is necessary for molecular oscillations in all three signaling pathways but does not function as an integral component of the oscillator. Small, irregular somites persist in abnormally posterior locations in the absence of -catenin and cycling clock gene expression. Conversely, Notch pathway genes continue to oscillate in the presence of stabilized -catenin but boundary formation is delayed and anteriorized. Together, these results suggest that the Wnt3a/-catenin pathway is permissive but not instructive for oscillating clock genes and that it controls the anterior-posterior positioning of boundary formation in the presomitic mesoderm (PSM). The Wnt3a/-catenin pathway does so by regulating the activation of the segment boundary determination genes Mesp2 and Ripply2 in the PSM through the activation of the Notch ligand Dll1 and the mesodermal transcription factors T and Tbx6. Spatial restriction of Ripply2 to the anterior PSM is ensured by the Wnt3a/-catenin-mediated repression of Ripply2 in posterior PSM. Thus, Wnt3a regulates somitogenesis by activating a network of interacting target genes that promote mesodermal fates, activate the segmentation clock, and position boundary determination genes in the anterior PSM.
This article has been cited by other articles:
|
|
|
|
 
Y. Yasuhiko, S. Kitajima, Y. Takahashi, M. Oginuma, H. Kagiwada, J. Kanno, and Y. Saga
Functional importance of evolutionally conserved Tbx6 binding sites in the presomitic mesoderm-specific enhancer of Mesp2
Development,
November 1, 2008;
135(21):
3511 - 3519.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. K. Hytonen, A. Grall, B. Hedan, S. Dreano, S. J. Seguin, D. Delattre, A. Thomas, F. Galibert, L. Paulin, H. Lohi, et al.
Ancestral T-Box Mutation Is Present in Many, but Not All, Short-Tailed Dog Breeds
J. Hered.,
October 14, 2008;
(2008)
esn085v1.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Grigoryan, P. Wend, A. Klaus, and W. Birchmeier
Deciphering the function of canonical Wnt signals in development and disease: conditional loss- and gain-of-function mutations of {beta}-catenin in mice
Genes & Dev.,
September 1, 2008;
22(17):
2308 - 2341.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Feller, A. Schneider, K. Schuster-Gossler, and A. Gossler
Noncyclic Notch activity in the presomitic mesoderm demonstrates uncoupling of somite compartmentalization and boundary formation
Genes & Dev.,
August 15, 2008;
22(16):
2166 - 2171.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Oginuma, Y. Niwa, D. L. Chapman, and Y. Saga
Mesp2 and Tbx6 cooperatively create periodic patterns coupled with the clock machinery during mouse somitogenesis
Development,
August 1, 2008;
135(15):
2555 - 2562.
[Abstract]
[Full Text]
[PDF]
|
|
|
© The Company of Biologists Ltd 2007
