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Generation of Dispersed Presomitic Mesoderm Cell Cultures for Imaging of the Zebrafish Segmentation Clock in Single Cells
Published on: July 24, 2014
Segment number and axial identity in a segmentation clock period mutant
Christian Schröter1, Andrew C Oates
1Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, D-01307 Dresden, Germany.
Current Biology : CB
|July 20, 2010
Summary
Altering the segmentation clock in zebrafish embryos reduced segment number. This finding suggests the clock controls segment count but not axial identity, offering evolutionary insights into body plan development.
Area of Science:
- Developmental biology
- Genetics
- Evolutionary biology
Background:
- Vertebrate body plans feature a species-specific number of segments, formed by somites budding from the presomitic mesoderm (PSM).
- The Clock and Wavefront model posits that somite number depends on the segmentation clock's period and PSM growth duration.
- The segmentation clock's oscillations may also dictate regional segment identity.
Purpose of the Study:
- To investigate the roles of the segmentation clock in determining somite number and axial identity.
- To test the Clock and Wavefront model in a zebrafish mutant with a slowed segmentation clock.
Main Methods:
- Utilized a zebrafish mutant with a specifically slowed segmentation clock.
- Analyzed somite number, hox gene expression, and posterior anatomical markers.
Main Results:
- The slowed segmentation clock reduced the total number of somites formed, as predicted.
- Hox gene expression and posterior markers corresponded to the reduced segment count in mutants.
- Axial identities were not instructed by the segmentation clock's oscillations.
Conclusions:
- Precise regulation of the segmentation clock period relative to axial growth establishes species-specific segment numbers.
- Modifications to the segmentation clock's period may have facilitated evolutionary changes in segment number independently of axial regionalization.
