Ontologic Perspective: Terminal Differentiation and Maturation as Differently Regulated Stages in Muscle Development

Abstract

Dr. Rowland has described the well defined and rather uniform phenotypic expression of Duchenne muscular dystrophy. Efforts to identify a trigger for the ineluctable sequence of degenerative changes in muscle associated with that disease have thus far been frustrated. Nevertheless, because the characteristic weakness appears only late in infancy, and for other reasons as well, a defect in the genetic regulation of muscle cell development seems likely. Recently acquired knowledge of protein synthesis and recently developed tools for the study of cellular development have opened the door to new efforts to monitor the developmental sequence from satellite cell to myotube-building myoblast and ultimately to adult mature myocyte. The presentations that follow will examine the requirements for muscle cell differentiation and maturation, the gene regulated stages of development and their possible involvement in the mechanisms of Duchenne dystrophy. The proteins of the myofibrils, myosins, actins and troponin have been and still are primary targets for study as they reflect the two distinct stages of muscle cell development, differentiation and maturation.