A Model of Somitogenesis
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A quantitative description of the molecular networks that sustain morphogenesis is one of the main challenges of developmental biology. In particular, a molecular understanding of the segmentation of the antero-posterior axis in vertebrates has yet to be achieved. This process known as somitogenesis is believed to result from the interactions between a well-studied genetic oscillator and a less established posterior-moving determination wavefront. Here we describe a molecular model for somitogenesis that couples a moving morphogen wavefront with the somitogenetic oscillator. The wavefront is due to a switch between stable states that results from reciprocal negative feedbacks of Retinoic Acid (RA) on the activation of a kinase ErK and of ErK on RA synthesis. We suggest a molecular mechanism by which that switch can be triggered by the somitogenetic clock. The model quantitatively accounts for the shortening of the pre-somitic mesoderm (PSM) in zebrafish in response to the decrease during somitogenesis in the concentration of a morphogen (Fgf8). The generality and robustness of the model allows for its validation (or invalidation) in other model organisms.
KeywordsMorphogenesis Somitogenesis Quantitative biology
We thank A.Goldbeter and V.Hakim for constructive criticism of our model. This work was partially supported by Grants ANR-10-LABX-54 MEMO LIFE and ANR-11-IDEX-0001-02 PSL* Research University and PSL Grants SuperLINE and MicroGUT.
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