Maternal wnt11 activates the canonical wnt signaling pathway required for axis formation in Xenopus embryos.
Wnt signaling pathways play essential roles in patterning and proliferation of embryonic and adult tissues. In many organisms, this signaling pathway directs axis formation. Although the importance of intracellular components of the pathway, including beta-catenin and Tcf3, has been established, the mechanism of their activation is uncertain. In Xenopus, the initiating signal that localizes beta-catenin to dorsal nuclei has been suggested to be intracellular and Wnt independent. Here, we provide three lines of evidence that the pathway specifying the dorsal axis is activated extracellularly in Xenopus embryos. First, we identify Wnt11 as the initiating signal. Second, we show that activation requires the glycosyl transferase X.EXT1. Third, we find that the EGF-CFC protein, FRL1, is also essential and interacts with Wnt11 to activate canonical Wnt signaling.
Tao
Qinghua
Q
Division of Developmental Biology, Cincinnati Children's Research Foundation, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA.
Yokota
Chika
C
Puck
Helbert
H
Kofron
Matt
M
Birsoy
Bilge
B
Yan
Dong
D
Asashima
Makoto
M
Wylie
Christopher C
CC
Lin
Xinhua
X
Heasman
Janet
J
D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005260:Female; D058851:GPI-Linked Proteins; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D051153:Wnt Proteins; D014981:Xenopus / Q000196:embryology / Q000378:metabolism*; D029867:Xenopus Proteins / Q000378:metabolism; D051176:beta Catenin; D000099058:Exostosin 1
C495266:CTNNB1 protein, Xenopus; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D058851:GPI-Linked Proteins; D006023:Glycoproteins; D018398:Homeodomain Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D051153:Wnt Proteins; D029867:Xenopus Proteins; D051176:beta Catenin; C096788:tdgf1.3 protein, Xenopus; C512785:wnt11b protein, Xenopus; D017351:N-Acetylglucosaminyltransferases; D000099058:Exostosin 1