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Updated: Aug 15, 2026

Generation of Dispersed Presomitic Mesoderm Cell Cultures for Imaging of the Zebrafish Segmentation Clock in Single Cells
Published on: July 24, 2014
Oscillations, clocks and segmentation
Yasumasa Bessho1, Ryoichiro Kageyama
1Institute for Virus Research Kyoto University Shogoin-Kawahara, Sakyo-ku Kyoto 606-8507, Japan.
Abstract:
Notch signalling molecules, such as the basic helix-loop-helix factors Hes1 and Hes7, periodically change their expression in the presomitic mesoderm, and each cycle of gene expression is associated with somite formation (every two hours in mouse). This cyclic expression is the manifestation of an intrinsic mechanism, called the segmentation clock, which is essential for coordinated somite segmentation. Interestingly, the oscillatory expression of Hes1 is observed in many cell types after serum stimulation, suggesting that this ultradian clock is not unique to presomitic mesoderm cells but widely distributed. This oscillation depends on the negative feedback loop, and once its promoter is constitutively activated, Hes1 seems to start oscillatory gene expression autonomously. Thus, Hes1 acts as a device that transduces a direct current of input into an alternating current, which ticks the hours in many biological systems.
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