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The chinless mutation and neural crest cell interactions in zebrafish jaw development
T F Schilling1, C Walker, C B Kimmel
1Institute of Neuroscience, University of Oregon, Eugene 97403, USA.
Development (Cambridge, England)
|May 1, 1996
Summary
Mutations in the chinless (chn) gene disrupt zebrafish head development by blocking neural crest cell differentiation into cartilage. This impacts jaw and gill skeletal patterning and muscle development.
Area of Science:
- Developmental Biology
- Genetics
- Neuroscience
Background:
- Neural crest cells are crucial for vertebrate head development, patterning the jaw and gill skeleton and musculature.
- The gene chinless (chn) has been identified as a key regulator in these developmental processes.
Purpose of the Study:
- To investigate the role of the chinless (chn) gene in zebrafish cranial neural crest cell differentiation and pharyngeal arch development.
- To elucidate the specific cellular and molecular mechanisms by which chn influences skeletal and muscular patterning.
Main Methods:
- Analysis of zebrafish chinless (chn) mutants.
- Fate mapping and gene expression studies to track cell differentiation and lineage.
- Mosaic analyses and cell transplantation experiments to determine cell-autonomous versus non-autonomous effects.
- Examination of pharyngeal arch development in wild-type and mutant embryos.
Main Results:
- chn mutants exhibit a complete lack of neural-crest-derived cartilage and mesoderm-derived muscles in all seven pharyngeal arches.
- Undifferentiated cartilage and muscle precursors are present in mutants, indicating a block in differentiation rather than a lack of precursors.
- Mosaic analyses reveal that chn acts directly within neural crest cells to promote cartilage differentiation.
- Transplantation of wild-type neural crest cells into mutant hosts rescues cartilage formation, suggesting chn's requirement in neural crest for skeletal development.
- Paraxial mesoderm-derived muscle development is dependent on the host genotype, implying neural crest signals influence muscle patterning.
Conclusions:
- The chinless (chn) gene is essential for the differentiation of cranial neural crest cells into pharyngeal cartilages in zebrafish.
- chn-dependent signaling from neural crest cells is required for the proper patterning of mesoderm-derived myocytes, thereby coordinating skeletal and muscular development in the head.
- These findings highlight a critical role for chinless in integrating skeletal and muscular development through neural crest-derived signals.