Musculoskeletal embryonic nuclear protein 1 (Mustn1 or Mustang) constitutes a family of short, approx 80 residue, proteins found in chordates. Mustn1 localises to the nucleus and specifically, spatially in mesenchymal cells of the developing limbs and tail as well as in the fracture callus, especially in periosteal osteoprogenitor cells, proliferating chondrocytes, and young active osteoblasts. It is highly expressed during embryogenesis and is necessary for both chondrocyte proliferation and differentiation []. It is inactivated in most adult tissues with the exception of skeletal muscle and tendon where is acutely and differentially expressed during bone regeneration [].
