TY - JOUR T1 - Fibroblast fusion to the muscle fiber regulates myotendinous junction formation JF - bioRxiv DO - 10.1101/2020.07.20.213199 SP - 2020.07.20.213199 AU - Wesal Yaseen-Badarneh AU - Ortal Kraft-Sheleg AU - Shelly Zaffryar-Eilot AU - Shay Melamed AU - Chengyi Sun AU - Douglas P. Millay AU - Peleg Hasson Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/07/21/2020.07.20.213199.abstract N2 - Vertebrate muscles and tendons are derived from distinct embryonic origins yet they must interact in order to facilitate muscle contraction and body movements. How robust muscle tendon junctions (MTJs) form to be able to withstand contraction forces is still not understood. Using techniques at a single cell resolution we reexamined the classical view of distinct identities for the tissues composing the musculoskeletal system. We identified fibroblasts that have switched on a myogenic program and demonstrate these dual identity cells fuse into the developing muscle fibers along the MTJs facilitating the introduction of fibroblast-specific transcripts into the elongating myofibers. We suggest this mechanism resulting in a hybrid muscle fiber, primarily along the fiber tips, enables a smooth transition from muscle fiber characteristics towards tendon features essential for forming robust MTJs. We propose that dual characteristics of junctional cells could be a common mechanism for generating stable interactions between tissues throughout the musculoskeletal system.Competing Interest StatementThe authors have declared no competing interest. ER -