PT - JOURNAL ARTICLE AU - Patrícia Gomes de Almeida AU - Pedro Rifes AU - Ana Patrícia Martins-Jesus AU - Gonçalo G. Pinheiro AU - Raquel P. Andrade AU - Sólveig Thorsteinsdóttir TI - A fibronectin mechanotransduction pathway translates segmentation clock oscillations into periodic somite formation AID - 10.1101/808121 DP - 2019 Jan 01 TA - bioRxiv PG - 808121 4099 - http://biorxiv.org/content/early/2019/10/22/808121.short 4100 - http://biorxiv.org/content/early/2019/10/22/808121.full AB - Somitogenesis starts with cyclic waves of expression of segmentation clock genes in the presomitic mesoderm (PSM) and culminates with periodic budding of somites in its anterior-most region. How cyclic clock gene expression is translated into timely morphological somite formation remains unclear. A posterior to anterior gradient of increasing fibronectin matrix complexity surrounds the PSM, suggesting that the mechanical properties of the matrix may play a role in regulating this transition. Here we interfered with the chick PSM fibronectin mechanotransduction pathway by perturbing (1) actomyosin-mediated contractility, (2) Rho-associated protein kinase function, (3) integrin-fibronectin binding and (4) fibronectin matrix assembly. Each treatment perturbed segmentation clock expression dynamics, meso1 expression and resulted in defective somitic clefts. A model is presented where the fibronectin matrix gradient participates in the PSM wavefront of maturation by activating a mechanotransduction signaling cascade ensuring the correct spatio-temporal conversion of cyclic segmentation clock gene expression into periodic somite formation.