ZFIN ID: ZDB-PUB-160320-10
Osterix/sp7 limits cranial bone initiation sites and is required for formation of sutures
Kague, E., Roy, P., Asselin, G., Hu, G., Stanley, A., Albertson, C., Simonet, J., Fisher, S.
Date: 2016
Source: Developmental Biology   413(2): 160-72 (Journal)
Registered Authors: Albertson, R. Craig, Fisher, Shannon
Keywords: Craniofacial skeleton, Osteogenesis, Osterix/sp7, Sutures, Zebrafish mutant
MeSH Terms:
  • Animals
  • Body Patterning
  • Bone Morphogenetic Proteins/metabolism
  • Cartilage/embryology
  • Cranial Sutures/embryology*
  • Humans
  • Mutation
  • Osteoblasts/cytology
  • Osteogenesis*/genetics
  • Signal Transduction
  • Skull/embryology
  • Transcription Factors/genetics
  • Transcription Factors/physiology*
  • Transcriptome
  • Zebrafish
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/physiology*
PubMed: 26992365 Full text @ Dev. Biol.
During growth, individual skull bones overlap at sutures, where osteoblast differentiation and bone deposition occur. Mutations causing skull malformations have revealed some required genes, but many aspects of suture regulation remain poorly understood. We describe a zebrafish mutation in osterix/sp7, which causes a generalized delay in osteoblast maturation. While most of the skeleton is patterned normally, mutants have specific defects in the anterior skull and upper jaw, and the top of the skull comprises a random mosaic of bones derived from individual initiation sites. Osteoblasts at the edges of the bones are highly proliferative and fail to differentiate, consistent with global changes in gene expression. We propose that signals from the bone itself are required for orderly recruitment of precursor cells and growth along the edges. The delay in bone maturation caused by loss of Sp7 leads to unregulated bone formation, revealing a new mechanism for patterning the skull and sutures.