7siIn Xenopus laevis somitogenesis, somitic blocks undergo coordinated movements resulting in their detachment from the rest of the mesodermal ridge, followed by a 90° rotation of the entire metamere. Here we investigated the function of type I cadherins in somitogenesis. Type I cadherins are Ca2+-dependent cell-cell adhesion molecules concentrated in the adherens junctions and highly expressed in the somitic tissue. We analyzed their role in somitogenesis by overexpressing either the intracellular (∆E) and the extracellular (C-trunc) dominant-negative forms of cadherin. The resulting phenotype was a downward bend of the anterior-posterior axis in tadpole stage embryos. 12/101 antigen and X-Myo-D expression were altered. Microscopy revealed disorganization of the myotomes. Conversely, segmentation was conserved at the microscopic and molecular levels.nonemixedGiacomello, Emiliana; Vallin, Jerome; Morali, Olivier; Coulter, Ivan S.; Boulekbache, Habib; Thiery, Jean P.; Broders, FlorenceGiacomello, Emiliana; Vallin, Jerome; Morali, Olivier; Coulter, Ivan S.; Boulekbache, Habib; Thiery, Jean P.; Broders, Florenc
