Related Experiment Video
Updated: May 19, 2026
Analysis of Craniomaxillofacial Malformations in Mice Using Three-dimensional Microcomputed Tomography
Published on: January 17, 2025
In vivo impact of Dlx3 conditional inactivation in neural crest-derived craniofacial bones
Olivier Duverger1, Juliane Isaac, Angela Zah
1Developmental Skin Biology Section, NIAMS, NIH, Bethesda, Maryland.
Abstract:
Mutations in DLX3 in humans lead to defects in craniofacial and appendicular bones, yet the in vivo activities related to Dlx3 function during normal skeletal development have not been fully elucidated. Here we used a conditional knockout approach to analyze the effects of neural crest deletion of Dlx3 on craniofacial bones development. At birth, mutant mice exhibit a normal overall positioning of the skull bones, but a change in the shape of the calvaria was observed. Molecular analysis of the genes affected in the frontal bones and mandibles from these mice identified several bone markers known to affect bone development, with a strong prediction for increased bone formation and mineralization in vivo. Interestingly, while a subset of these genes were similarly affected in frontal bones and mandibles (Sost, Mepe, Bglap, Alp, Ibsp, Agt), several genes, including Lect1 and Calca, were specifically affected in frontal bones. Consistent with these molecular alterations, cells isolated from the frontal bone of mutant mice exhibited increased differentiation and mineralization capacities ex vivo, supporting cell autonomous defects in neural crest cells. However, adult mutant animals exhibited decreased bone mineral density in both mandibles and calvaria, as well as a significant increase in bone porosity. Together, these observations suggest that mature osteoblasts in the adult respond to signals that regulate adult bone mass and remodeling. This study provides new downstream targets for Dlx3 in craniofacial bone, and gives additional evidence of the complex regulation of bone formation and homeostasis in the adult skeleton.
Insights
Neural crest deletion of Dlx3 impacts craniofacial bone development, leading to altered bone shape and mineralization in mice. Adult mice show reduced bone density and increased porosity, revealing Dlx3's complex role in skeletal homeostasis.
Area of Science:
- Genetics and Developmental Biology
- Orthopedics and Skeletal Biology
- Craniofacial Development
Background:
- Mutations in DLX3 cause human skeletal defects, but its precise role in normal skeletal development is unclear.
- The function of Dlx3 in neural crest cells during craniofacial bone development requires further investigation.
Purpose of the Study:
- To investigate the in vivo function of Dlx3 in neural crest cells during craniofacial bone development using a conditional knockout mouse model.
- To identify downstream targets of Dlx3 and understand its role in bone formation, mineralization, and homeostasis.
Main Methods:
- Conditional knockout of Dlx3 in neural crest cells of mice.
- Analysis of craniofacial bone morphology and histology at birth.
- Molecular analysis of bone marker gene expression in frontal bones and mandibles.
- Ex vivo analysis of bone cell differentiation and mineralization.
- Assessment of bone mineral density and microarchitecture in adult mice.
Main Results:
- Conditional knockout of Dlx3 in neural crest cells resulted in altered calvarial shape at birth.
- Molecular analysis revealed altered expression of bone development genes, with predictions of increased bone formation and mineralization.
- Cells from mutant frontal bones showed enhanced differentiation and mineralization ex vivo.
- Adult mutant mice exhibited decreased bone mineral density and increased bone porosity in mandibles and calvaria.
Conclusions:
- Dlx3 plays a crucial role in regulating craniofacial bone development and homeostasis.
- Neural crest-derived Dlx3 influences cell-autonomous bone formation and mineralization.
- Dlx3 affects adult bone mass and remodeling, highlighting its complex role throughout skeletal life.
