Wnt/β-catenin dependent cell proliferation underlies segmented lateral line morphogenesis.
Morphogenesis is a fascinating but complex and incompletely understood developmental process. The sensory lateral line system consists of only a few hundred cells and is experimentally accessible making it an excellent model system to interrogate the cellular and molecular mechanisms underlying segmental morphogenesis. The posterior lateral line primordium periodically deposits prosensory organs as it migrates to the tail tip. We demonstrate that periodic proneuromast deposition is governed by a fundamentally different developmental mechanism than the classical models of developmental periodicity represented by vertebrate somitogenesis and early Drosophila development. Our analysis demonstrates that proneuromast deposition is driven by periodic lengthening of the primordium and a stable Wnt/β-catenin activation domain in the leading region of the primordium. The periodic lengthening of the primordium is controlled by Wnt/β-catenin/Fgf-dependent proliferation. Once proneuromasts are displaced into the trailing Wnt/β-catenin-free zone they are deposited. We have previously shown that Wnt/β-catenin signaling induces Fgf signaling and that interactions between these two pathways regulate primordium migration and prosensory organ formation. Therefore, by coordinating migration, prosensory organ formation and proliferation, localized activation of Wnt/β-catenin signaling in the leading zone of the primordium plays a crucial role in orchestrating lateral line morphogenesis.
University of Utah Medical School, Dept. of Neurobiology and Anatomy, MREB 401, Salt Lake City, UT 84132, USA.
Andy
A
Aman
Minhtu
M
Nguyen
Tatjana
T
Piotrowski
D000818:Animals; D016590:Aphidicolin; D001973:Bromodeoxyuridine; D049109:Cell Proliferation / Q000187:drug effects; D017931:DNA Primers / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000196:embryology; D005346:Fibroblast Growth Factors / Q000378:metabolism; D055786:Gene Knockout Techniques; D006918:Hydroxyurea; D017403:In Situ Hybridization; D020287:In Situ Nick-End Labeling; D053403:Lateral Line System / Q000196:embryology*; D009024:Morphogenesis / Q000502:physiology*; D011758:Pyrroles / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D059008:Time-Lapse Imaging; D014157:Transcription Factors / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology*; D051176:beta Catenin / Q000378:metabolism*
D017931:DNA Primers; D011758:Pyrroles; C105686:SU 5402; D014157:Transcription Factors; D051153:Wnt Proteins; D051176:beta Catenin; C065788:transcription factor PEA3; D016590:Aphidicolin; D005346:Fibroblast Growth Factors; D001973:Bromodeoxyuridine; D006918:Hydroxyurea