ZFIN ID: ZDB-PUB-090929-7
Craniofacial skeletal defects of adult zebrafish Glypican 4 (knypek) mutants
LeClair, E.E., Mui, S.R., Huang, A., Topczewska, J.M., and Topczewski, J.
Date: 2009
Source: Developmental dynamics : an official publication of the American Association of Anatomists   238(10): 2550-2563 (Journal)
Registered Authors: LeClair, Elizabeth E., Mui, Stephanie, Topczewska, Jolanta, Topczewski, Jacek
Keywords: zebrafish, glypican, knypek, craniofacial, skull, jaw, bone, cartilage, morphometrics
MeSH Terms:
  • Animals
  • Animals, Genetically Modified
  • Body Patterning*
  • Cartilage*/abnormalities
  • Cartilage*/anatomy & histology
  • Cartilage*/growth & development
  • Facial Bones*/abnormalities
  • Facial Bones*/anatomy & histology
  • Facial Bones*/growth & development
  • Gene Knockdown Techniques
  • Glypicans/genetics
  • Glypicans/metabolism*
  • Humans
  • Phenotype
  • Skull*/abnormalities
  • Skull*/anatomy & histology
  • Skull*/growth & development
  • Zebrafish*/abnormalities
  • Zebrafish*/anatomy & histology
  • Zebrafish*/growth & development
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed: 19777561 Full text @ Dev. Dyn.
The heparan sulfate proteoglycan Glypican 4 (Gpc4) is part of the Wnt/planar cell polarity pathway, which is required for convergence and extension during zebrafish gastrulation. To observe Glypican 4-deficient phenotypes at later stages, we rescued gpc4(-/-) (knypek) homozygotes and raised them for more than one year. Adult mutants showed diverse cranial malformations of both dermal and endochondral bones, ranging from shortening of the rostral-most skull to loss of the symplectic. Additionally, the adult palatoquadrate cartilage was disorganized, with abnormal chondrocyte orientation. To understand how the palatoquadrate cartilage normally develops, we examined a juvenile series of wild type and mutant specimens. This identified two novel domains of elongated chondrocytes in the larval palatoquadrate, which normally form prior to endochondral ossification. In contrast, gpc4(-/-) larvae never form these domains, suggesting a failure of chondrocyte orientation, though not differentiation. Our findings implicate Gpc4 in the regulation of zebrafish cartilage and bone morphogenesis.