Related Experiment Video
Updated: Aug 6, 2026
09:16
Analyzing Craniofacial Morphogenesis in Zebrafish Using 4D Confocal Microscopy
Published on: January 30, 2014
Differential sensitivity to SHH signaling and neural crest-mediated Gas1 expression regulate jaw size during
Zuzana Vavrušová1, Daniel B Chu1, An Nguyen1
1Department of Orthopaedic Surgery, University of California San Francisco, San Francisco, California, USA.
Summary
Changes in Growth Arrest-Specific 1 (GAS1) expression in neural crest mesenchyme (NCM) cells influence jaw size. This finding is key to understanding jaw development, birth defects, and evolutionary adaptations in jaw size.
Area of Science:
- Developmental biology
- Evolutionary biology
- Genetics
Background:
- Jaw size development is critical for preventing birth defects and enabling evolutionary adaptation.
- Neural crest mesenchyme (NCM) cells establish jaw size by migrating into mandibular primordia.
- Sonic Hedgehog (SHH) signaling pathway is essential for NCM interactions with mandibular epithelium, promoting jaw outgrowth.
Purpose of the Study:
- To investigate if NCM-mediated regulation of the SHH pathway explains species-specific differences in jaw size evolution.
- To explore the role of Growth Arrest-Specific 1 (GAS1) in jaw size determination.
Main Methods:
- Analysis of SHH pathway member expression in duck and quail mandibular primordia.
- Quail-duck chimera generation to study NCM regulation of GAS1.
- Gain- and loss-of-function experiments for GAS1 in NCM.
- Analysis of differential gene expression and promoter/coding sequences of GAS1.
Main Results:
- GAS1 expression is significantly higher (20-75 fold) in duck mandibular primordia compared to quail.
- GAS1 expression is regulated by NCM, and species-specific sensitivity to SHH signaling, particularly involving GAS1, was observed.
- Altering GAS1 levels in NCM affected cell number, jaw size, and modulated SHH, WNT, and cell cycle pathways.
- Differences in GAS1 promoter and coding sequences between duck and quail were identified.
Conclusions:
- Modifications in GAS1 expression and function appear to regulate jaw size during development.
- These changes in GAS1 may play a role in developmental disorders and evolutionary changes in jaw morphology.
Keywords:
Gas1SHH signalingavian embryosevolutionary developmental biologyjaw sizeneural crestquail‐duck chimerasspecies‐specific patternMore Related Videos
Related Concept Videos
01:51Determination
During embryogenesis, cells become progressively committed to different fates through a two-step process: specification followed by determination. Specification is demonstrated by removing a segment of an early embryo, “neutrally” culturing the tissue in vitro—for example, in a petri dish with simple medium—and then observing the derivatives. If the cultured region gives rise to cell types that it would normally generate in the embryo, this means that it is specified. In contrast, determination...
02:33Hedgehog Signaling Pathway
The Hedgehog gene (Hh) was first discovered due to its control of the growth of disorganized, hair-like bristles phenotype in Drosophila, much like hedgehog spines. Hh plays a crucial role in the development of organs and the maintenance of homeostasis in both invertebrates and vertebrates. However, while Drosophila has only one Hh protein, mammals have multiple functional Hedgehog proteins - Sonic (Shh), Desert (Dhh), and Indian Hedgehog (Ihh). All of these homologous proteins have adapted to...
03:14Notch Signaling Pathway
The Notch signaling pathway is a major intracellular signaling pathway that is highly conserved over a broad spectrum of metazoan species. It stands unique from other intracellular signaling mechanisms in animals because notch protein itself acts as the receptor as well as the primary signaling molecule.
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...