1. A new transgenic reporter line reveals Wnt-dependent Snai2 re-expression and cranial neural crest differentiation in Xenopus.
- Author
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Li J, Perfetto M, Materna C, Li R, Thi Tran H, Vleminckx K, Duncan MK, and Wei S
- Subjects
- ADAM Proteins genetics, ADAM Proteins metabolism, Animals, Animals, Genetically Modified, Cell Differentiation drug effects, Cell Differentiation genetics, Embryo, Nonmammalian, Embryonic Development drug effects, Embryonic Development physiology, Gene Expression Regulation, Developmental drug effects, Gene Expression Regulation, Developmental genetics, Gene Knockdown Techniques, Genes, Reporter genetics, Green Fluorescent Proteins chemistry, Green Fluorescent Proteins genetics, Heterocyclic Compounds, 3-Ring pharmacology, Imides pharmacology, Membrane Proteins genetics, Membrane Proteins metabolism, Neural Crest cytology, Quinolines pharmacology, Wnt Proteins antagonists & inhibitors, Wnt Proteins genetics, Wnt Signaling Pathway drug effects, Wnt Signaling Pathway genetics, Wnt Signaling Pathway physiology, Xenopus Proteins genetics, Xenopus laevis genetics, Brain embryology, Neural Crest physiology, Transcription Factors metabolism, Wnt Proteins metabolism, Xenopus Proteins metabolism, Xenopus laevis embryology
- Abstract
During vertebrate embryogenesis, the cranial neural crest (CNC) forms at the neural plate border and subsequently migrates and differentiates into many types of cells. The transcription factor Snai2, which is induced by canonical Wnt signaling to be expressed in the early CNC, is pivotal for CNC induction and migration in Xenopus. However, snai2 expression is silenced during CNC migration, and its roles at later developmental stages remain unclear. We generated a transgenic X. tropicalis line that expresses enhanced green fluorescent protein (eGFP) driven by the snai2 promoter/enhancer, and observed eGFP expression not only in the pre-migratory and migrating CNC, but also the differentiating CNC. This transgenic line can be used directly to detect deficiencies in CNC development at various stages, including subtle perturbation of CNC differentiation. In situ hybridization and immunohistochemistry confirm that Snai2 is re-expressed in the differentiating CNC. Using a separate transgenic Wnt reporter line, we show that canonical Wnt signaling is also active in the differentiating CNC. Blocking Wnt signaling shortly after CNC migration causes reduced snai2 expression and impaired differentiation of CNC-derived head cartilage structures. These results suggest that Wnt signaling is required for snai2 re-expression and CNC differentiation.
- Published
- 2019
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