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The zebrafish Nodal signal Squint functions as a morphogen
1Developmental Genetics Program, Skirball Institute of Biomolecular Medicine, Department for Cell Biology, New York University School of Medicine, New York 10016, USA.
Nature
|June 1, 2001
Summary
Squint and Cyclops are transforming growth factor-beta signals crucial for zebrafish mesoderm development. Researchers found Squint acts as a secreted morphogen, directly influencing cells at a distance without a relay mechanism.
Area of Science:
- Developmental biology
- Molecular signaling
- Zebrafish embryogenesis
Background:
- Secreted morphogens regulate cellular responses concentration-dependently and act at a distance.
- The role of morphogens in vertebrate mesoderm induction and patterning remains controversial.
- It is unclear if endogenous mesoderm inducers act directly, locally, or via relay mechanisms.
Purpose of the Study:
- To investigate the morphogen properties of Cyclops and Squint in zebrafish mesoderm formation.
- To determine if these Nodal-related transforming growth factor-beta signals function as direct morphogens.
- To elucidate the mechanism of action for Squint and Cyclops during mesoderm patterning.
Main Methods:
- Utilized zebrafish as a model organism.
- Analyzed the effects of varying concentrations of Squint and Cyclops.
- Assessed the induction of downstream genes.
- Investigated the direct action at a distance of these signaling molecules.
Main Results:
- Both Squint and Cyclops, at different concentrations, induced distinct downstream genes.
- Only Squint demonstrated the ability to function directly at a distance.
- Squint's action did not necessitate a relay mechanism.
Conclusions:
- Squint functions as a secreted morphogen in zebrafish mesoderm development.
- Squint acts directly at a distance, independent of a relay system.
- These findings clarify the role of Squint in mesoderm patterning.
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