Unorthodox myogenesis: possible developmental significance and implications for tissue histogenesis and regeneration

G. Cossu

Department of Histology and Medical Embryology, University of Rome "La Sapienza", Rome, Italy

Offprint requests to: Dr. Guiul io Cossu , Institute of Histology and General Embryology, University of Rome .. La Sapienza», 14 Via A. Scarpa, 00161 Italy

Summary. During the last few years several reports have described the occurrence of skeletal myogenesis in cells derived from embryonic, fetal and perinatal tissues that usually do not contribute to skeletal muscle in the adult vertebrate body. Aft er a bri e f des cripti on of c urre nt ideas on myogenic de termin ation in higher vertebrates, three examples of this uno rth o dox myoge nes is will be described: 1) the occurrence of myogenes is in chick e pibl as t ce ll s, c ultured in is ol a tion in se rum-f ree medium ; 2) the prese nce of c e ll s end owed with myogenic potential in the embryonic mouse neural tube; and 3) the occurre nce of s po nt aneous o r indu ced myogenesis in mesenchymal cells during fe tal and postnatal life. A poss ibl e embryo logica l bas is for uno rthodox myogenesis, in relati on to gas trul ati on and mo rphogenetic fields, is then presented. It is also proposed that unorthodox myogenesis may represent a compensatory mechanism for higher vertebrates that have lost much of the regeneration potential of lower vertebrates. Histol Histopathol 12, 755-760 (1997)

Key words: Myogenesis, Determination, Histogenesis, Differe ntiation, Myogenic genes

DOI: 10.14670/HH-12.755