Inhibitory Gli3 Activity Negatively Regulates Wnt/β-Catenin Signaling

Summary The Hedgehog (Hh) and Wingless (Wnt) families of secreted signaling molecules have key roles in embryonic development and adult tissue homeostasis [1–3]. In the developing neural tube, Wnt and Shh, emanating from dorsal and ventral regions, respectively, have been proposed to govern the proliferation and survival of neural progenitors [4–10]. Surprisingly, Shh is required for the growth and survival of cells in both ventral and dorsal neural tube [11]. Here we demonstrate that inhibition of Shh signaling causes a reduction in Wnt-mediated transcriptional activation. This reduction requires Gli3. Assays in embryos and cell lines indicate that repressor forms of the Hh-regulated transcription factor, Gli3 (Gli3R), which are generated in the absence of Hh signaling, inhibit canonical Wnt signaling. Gli3R acts by antagonizing active forms of the Wnt transcriptional effector, β-catenin. Consistent with this, Gli3R appears to physically interact with the carboxy-terminal domain of β-catenin, a region that includes the transactivation domain. These data offer an explanation for the proliferative defects in Shh null embryos and suggest a novel mechanism for crosstalk between the Hh and Wnt pathways.

[1]  R. Nusse,et al.  The Wnt signaling pathway in development and disease. , 2004, Annual review of cell and developmental biology.

[2]  Philip A Beachy,et al.  Hedgehog-Regulated Processing of Gli3 Produces an Anterior/Posterior Repressor Gradient in the Developing Vertebrate Limb , 2000, Cell.

[3]  Yasunori Tanaka,et al.  Sonic Hedgehog-induced Activation of the Gli1Promoter Is Mediated by GLI3* , 1999, The Journal of Biological Chemistry.

[4]  Hans Clevers,et al.  Activation of β-Catenin-Tcf Signaling in Colon Cancer by Mutations in β-Catenin or APC , 1997, Science.

[5]  Andrew P McMahon,et al.  A mitogen gradient of dorsal midline Wnts organizes growth in the CNS. , 2002, Development.

[6]  A. Joyner,et al.  All mouse ventral spinal cord patterning by hedgehog is Gli dependent and involves an activator function of Gli3. , 2004, Developmental cell.

[7]  M. Nakafuku,et al.  Regulation of Gli2 and Gli3 activities by an amino-terminal repression domain: implication of Gli2 and Gli3 as primary mediators of Shh signaling. , 1999, Development.

[8]  M. Scott,et al.  Antagonizing cAMP-dependent protein kinase A in the dorsal CNS activates a conserved Sonic hedgehog signaling pathway. , 1996, Development.

[9]  R. Kemler,et al.  The C-terminal transactivation domain of β-catenin is necessary and sufficient for signaling by the LEF-1/β-catenin complex in Xenopus laevis , 1999, Mechanisms of Development.

[10]  H Weissig,et al.  Assembly of the cadherin-catenin complex in vitro with recombinant proteins. , 1994, Journal of cell science.

[11]  P. Beachy,et al.  Cyclopia and defective axial patterning in mice lacking Sonic hedgehog gene function , 1996, Nature.

[12]  Andrew P. McMahon,et al.  Sonic hedgehog Regulates Proliferation and Inhibits Differentiation of CNS Precursor Cells , 1999, The Journal of Neuroscience.

[13]  H. Weintraub,et al.  Expression of achaete-scute homolog 3 in Xenopus embryos converts ectodermal cells to a neural fate. , 1994, Genes & development.

[14]  J. Briscoe,et al.  A gradient of Gli activity mediates graded Sonic Hedgehog signaling in the neural tube. , 2005, Genes & development.

[15]  Randall T. Moon,et al.  The transcriptional coactivator CBP interacts with beta-catenin to activate gene expression. , 2000, The Journal of cell biology.

[16]  A. Joyner,et al.  A mouse model of Greig cephalo–polysyndactyly syndrome: the extra–toesJ mutation contains an intragenic deletion of the Gli3 gene , 1993, Nature Genetics.

[17]  H Clevers,et al.  The chromatin remodelling factor Brg‐1 interacts with β‐catenin to promote target gene activation , 2001, The EMBO journal.

[18]  Hans Clevers,et al.  XTcf-3 Transcription Factor Mediates β-Catenin-Induced Axis Formation in Xenopus Embryos , 1996, Cell.

[19]  Sandipan Chatterjee,et al.  Wnt/wingless Signaling Requires Bcl9/legless-mediated Recruitment of Pygopus to the Nuclear Beta-catenin-tcf Complex , 2022 .

[20]  Yamamura Ken-ichi,et al.  Efficient selection for high-expression transfectants with a novel eukaryotic vector , 1991 .

[21]  B. Alman,et al.  Suppressor of fused negatively regulates beta-catenin signaling. , 2001, The Journal of biological chemistry.

[22]  P. Ingham,et al.  Hedgehog signaling in animal development: paradigms and principles. , 2001, Genes & development.

[23]  B. Alman,et al.  Suppressor of Fused Negatively Regulates β-Catenin Signaling* , 2001, The Journal of Biological Chemistry.

[24]  A. Joyner,et al.  A mouse model of Greig cephalapolysyndactyly syndrome: the extra-toes J mutation contains an intragenic deletion of the Gli3 gene , 1998, Nature Genetics.

[25]  David S. Parker,et al.  Pygopus, a nuclear PHD-finger protein required for Wingless signaling in Drosophila. , 2002, Development.

[26]  T. Jessell,et al.  A hedgehog-insensitive form of patched provides evidence for direct long-range morphogen activity of sonic hedgehog in the neural tube. , 2001, Molecular cell.

[27]  E. Fearon,et al.  Regulation of β-catenin transformation by the p300 transcriptional coactivator , 2000 .

[28]  S. Scherer,et al.  Failure of a medulloblastoma-derived mutant of SUFU to suppress WNT signaling , 2004, Oncogene.

[29]  J. Briscoe,et al.  The Sonic hedgehog pathway independently controls the patterning, proliferation and survival of neuroepithelial cells by regulating Gli activity , 2006, Development.

[30]  A. R. I. Altaba.  Gli proteins encode context-dependent positive and negative functions: implications for development and disease , 1999 .

[31]  J. Taipale,et al.  The Hedgehog and Wnt signalling pathways in cancer , 2001, Nature.

[32]  Choun-Ki Joo,et al.  Wnt/β-Catenin/Tcf Signaling Induces the Transcription of Axin2, a Negative Regulator of the Signaling Pathway , 2002, Molecular and Cellular Biology.

[33]  K. Kinzler,et al.  Constitutive Transcriptional Activation by a β-Catenin-Tcf Complex in APC−/− Colon Carcinoma , 1997, Science.

[34]  R. Krumlauf,et al.  The Wnt/beta-catenin pathway posteriorizes neural tissue in Xenopus by an indirect mechanism requiring FGF signalling. , 2001, Developmental biology.

[35]  C. Chiang,et al.  Specification of ventral neuron types is mediated by an antagonistic interaction between Shh and Gli3 , 2000, Nature Neuroscience.

[36]  P. McCrea,et al.  Embryonic axis induction by the armadillo repeat domain of beta- catenin: evidence for intracellular signaling , 1995, The Journal of cell biology.

[37]  A. McMahon,et al.  Sonic hedgehog regulates growth and morphogenesis of the tooth. , 2000, Development.

[38]  W F Bodmer,et al.  Beta-catenin mutations in cell lines established from human colorectal cancers. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[39]  T. Kornberg,et al.  Expression of the vertebrate Gli proteins in Drosophila reveals a distribution of activator and repressor activities. , 2000, Development.

[40]  R. Keynes,et al.  A critical role for sonic hedgehog signaling in the early expansion of the developing brain , 2002, Nature Neuroscience.

[41]  B. Brunk,et al.  Sonic hedgehog controls epaxial muscle determination through Myf5 activation. , 1999, Development.

[42]  Carmen Birchmeier,et al.  beta-Catenin signals regulate cell growth and the balance between progenitor cell expansion and differentiation in the nervous system. , 2003, Developmental biology.