Live imaging and genetic analysis of mouse notochord formation reveals regional morphogenetic mechanisms.
The node and notochord have been extensively studied as signaling centers in the vertebrate embryo. The morphogenesis of these tissues, particularly in mouse, is not well understood. Using time-lapse live imaging and cell lineage tracking, we show the notochord has distinct morphogenetic origins along the anterior-posterior axis. The anterior head process notochord arises independently of the node by condensation of dispersed cells. The trunk notochord is derived from the node and forms by convergent extension. The tail notochord forms by node-derived progenitors that actively migrate toward the posterior. We also reveal distinct genetic regulation within these different regions. We show that Foxa2 compensates for and genetically interacts with Noto in the trunk notochord, and that Noto has an evolutionarily conserved role in regulating axial versus paraxial cell fate. Therefore, we propose three distinct regions within the mouse notochord, each with unique morphogenetic origins.
Program in Developmental & Stem Cell Biology, Hospital for Sick Children Research Institute, Toronto, Ontario M5G 1X8, Canada.
Yojiro
Y
Yamanaka
Owen J
OJ
Tamplin
Anja
A
Beckers
Achim
A
Gossler
Janet
J
Rossant
D000818:Animals; D019070:Cell Lineage; D005260:Female; D005775:Gastrula; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D051542:Hepatocyte Nuclear Factor 3-beta / Q000235:genetics / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D051379:Mice / Q000196:embryology; D008813:Mice, Inbred ICR; D008822:Mice, Transgenic; D009024:Morphogenesis; D009672:Notochord / Q000196:embryology / Q000502:physiology*; D011247:Pregnancy; D019076:Transgenes / Q000502:physiology
C496503:Foxa2 protein, mouse; D018398:Homeodomain Proteins; C489656:Not protein, mouse; C485184:enhanced green fluorescent protein; D051542:Hepatocyte Nuclear Factor 3-beta; D049452:Green Fluorescent Proteins