Pax3 regulates morphogenetic cell behavior in vitro coincident with activation of a PCP/non-canonical Wnt-signaling cascade.
Mutations to Pax3 and other Pax family genes in both mice and humans result in numerous tissue-specific morphological defects. Little is known, however, about the cellular and molecular mechanisms by which Pax genes regulate morphogenesis. We previously showed that Pax3 induces cell aggregation and a mesenchymal-to-epithelial transition in Saos-2 cells. We show here that Pax3-induced aggregates arise through the formation of distinct structures involving cell rearrangements and cell behaviors resembling those that occur during gastrulation and neurulation known as convergent extension. During these Pax3-induced processes, Dishevelled and Frizzled are localized to the actin cytoskeleton and both proteins coimmunoprecipitate focal adhesion components from detergent-insoluble cell fractions. We show further that these Pax3-induced cell movements are associated with activation of a Wnt-signaling cascade, resulting in induction and activation of c-Jun-N-terminal kinase/stress activated protein kinase (JNK/SAPK). All of these Wnt-signaling factors exhibit altered subcellular distribution in Pax3-expressing cells. In particular, we show the localization of JNK/SAPK to both the nucleus and to cytoplasmic multi-vesicular structures. These data show that Pax3 regulates morphogenetic cell behavior and that regulation of a conserved, planar cell polarity/noncanonical Wnt-signaling cascade entailing JNK activation is a function of Pax3 activity.
Wiggan
O'Neil
O
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5S 1A8 Canada.
Hamel
Paul A
PA
D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D000256:Adenoviridae / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002449:Cell Aggregation / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D016764:Cell Polarity; D048429:Cell Size; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000072261:Dishevelled Proteins; D004789:Enzyme Activation; D022001:Focal Adhesions / Q000378:metabolism; D051157:Frizzled Receptors; D017930:Genes, Reporter; D006801:Humans; D007150:Immunohistochemistry; D048031:JNK Mitogen-Activated Protein Kinases; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D012516:Osteosarcoma; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; D010750:Phosphoproteins / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D016596:Vinculin / Q000378:metabolism; D051153:Wnt Proteins; D029961:Zebrafish Proteins
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D000072261:Dishevelled Proteins; D051157:Frizzled Receptors; D000072041:PAX3 Transcription Factor; C489409:PAX3 protein, human; D051761:Paired Box Transcription Factors; D010750:Phosphoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D051153:Wnt Proteins; D029961:Zebrafish Proteins; C489412:pax3a protein, zebrafish; D016596:Vinculin; C068686:Pax3 protein, mouse; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases