Wnt/β-catenin signaling is an evolutionarily conserved determinant of chordate dorsal organizer

• Published in: eLife 2020-05, Vol.9
• Main Authors: Kozmikova, Iryna, Kozmik, Zbynek
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Asymmetry; axial patterning; beta Catenin - metabolism; Biological Evolution; body plan; branchiostoma floridae; branchiostoma lanceolatum; Cell fate; Cephalochordata; Developmental Biology; Embryos; evolution; Evolutionary Biology; Evolutionary conservation; Gene expression; Goosecoid Protein - metabolism; HEK293 Cells; Humans; Lancelets - embryology; Lancelets - metabolism; Medical research; Microinjection; Nodal Protein - metabolism; Proteins; Smad2 Protein - metabolism; Transcription factors; Vertebrates; Wnt protein; Wnt Signaling Pathway; wnt/β-catenin signaling; β-Catenin
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.56817

Deciphering the mechanisms of axis formation in amphioxus is a key step to understanding the evolution of chordate body plan. The current view is that Nodal signaling is the only factor promoting the dorsal axis specification in the amphioxus, whereas Wnt/β-catenin signaling plays no role in this process. Here, we re-examined the role of Wnt/βcatenin signaling in the dorsal/ventral patterning of amphioxus embryo. We demonstrated that the spatial activity of Wnt/β-catenin signaling is located in presumptive dorsal cells from cleavage to gastrula stage, and provided functional evidence that Wnt/β-catenin signaling is necessary for the specification of dorsal cell fate in a stage-dependent manner. Microinjection of and mRNA induced ectopic dorsal axis in neurulae and larvae. Finally, we demonstrated that Nodal and Wnt/β-catenin signaling cooperate to promote the dorsal-specific gene expression in amphioxus gastrula. Our study reveals high evolutionary conservation of dorsal organizer formation in the chordate lineage.