Zebrafish Wnt9b Patterns the First Pharyngeal Arch into D-I-V Domains and Promotes Anterior-Medial Outgrowth

作     者：Henry Wells Jackson Divakar Prakash Mark Litaker Tracie Ferreira Peter A. Jezewski 

作者机构：Department of Genetics University of Alabama at Birmingham Birmingham USA University of Alabama at Birmingham School of Dentistry Institute of Oral Health Research Birmingham USA Department of Clinical and Community Sciences University of Alabama at Birmingham School of Dentistry Birmingham USA Department of Bioengineering University of Massachusetts Dartmouth Dartmouth MA USA Department of Pediatric Dentistry University of Alabama at Birmingham School of Dentistry Birmingham AL USA 

出 版 物：《American Journal of Molecular Biology》 (美国分子生物学期刊（英文）)

年 卷 期：2015年第5卷第3期

页      面：57-83页

学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

主　　题：Cleft Morphogenesis Patterning Cranial Neural Crest Cell Pharyngeal Arch Primary/Secondary Mouth 

摘      要：Disrupted morphogenesis and growth of the embryonic maxillary jaw lead to oral facial clefting in humans (OFC) and result in an incompletely formed secondary mouth and face. A requirement for Wnt signaling and Wnt9b in particular are postulated in the etiology of OFC from association studies in humans and from animal models. Loss of murine Wnt9b leads to reduced upper jaw (maxillary) outgrowth and OFC, though the signaling architecture leading to this phenotype is poorly understood. Previous murine Wnt9b studies largely overlooked cranial neural crest cell (CNCC) patterning events and instead focused on later events during fusion of facial prominences. Using zebrafish and a morpholino-mediated knockdown approach, we demonstrate functional requirements for Wnt9b signaling during two crucial stages of facial development: 1) CNCC patterning into Dorsal-Intermediate-Ventral (D-I-V) domains;and 2) facial outgrowth during the primary to secondary mouth transition (PM to SM). Zebrafish embryos deficient for Wnt9b (Wnt9b morphants) exhibit an open bite with fused jaw joints as well as a flat face. Open bite and jaw joint fusion in Wnt9b morphants phenocopies characteristics of edn1 pathway is mutant zebrafish with disrupted D-I-V patterning of CNCC. Expression studies show Wnt9b morphants exhibit perturbed expression of edn1 signaling targets including dlx2a, jag1b, and msxe, consistent with disrupted CNCC patterning. Wnt9b morphant upper jaws have stunted outgrowth reminiscent of murine Wnt9b mutants and Wnt9b morphant skulls phenocopy the broad class of foreshortened skull zebrafish mutants known as hammerheads. Wnt9b morphants show upregulated expression of pitx2a after the opening of the primary mouth and disrupted expression of Wnt5b which is consistent with disrupted chondrocyte stacking. Strong upregulation of dorsal mesodermal frzb expression in the prechordal plate of Wnt9b morphants suggests a role for Wnt9b in primary mouth induction or maintenance. Collectively