PAPC couples the Segmentation Clock to somite morphogenesis by regulating N-cadherin dependent adhesion

Vertebrate segmentation is characterized by the periodic formation of epithelial somites from the mesenchymal presomitic mesoderm (PSM). How the rhythmic signaling pulse delivered by the Segmentation Clock is translated into the periodic morphogenesis of somites remains poorly understood. Here, we focused on the role of Paraxial protocadherin (PAPC/Pcdh8) in this process. We show that in chicken and mouse embryos, PAPC expression is tightly regulated by the Clock and Wavefront system in the posterior PSM. We observed that PAPC exhibits a striking complementary pattern to N-Cadherin (CDH2), marking the interface of the future somite boundary in the anterior PSM. Gain and loss of function of P