Regulation of Avian Skeletal Muscle Development and Maturation

Abstract

The chick has served as a useful model for studies on vertebrate development. Easy access to the embryo through the shell and the ready availability of large numbers of embryos at known developmental stages have contributed to the avian egg's popularity as a research model. Early research with the avian embryo described the differentiation and morphogenesis of the single cell egg into a free living chick (1). In the case of skeletal muscle, the origin and timing of mesodermal tissue differentiation and migration into somites and then skeletal muscle was followed. More recently, embryonic skeletal muscle precursors have been removed and cultured in vitro. Using combinations of in vivo and in vitro approaches, it has become apparent that the progenitors of muscle, the myoblasts, divide repeatedly and then cease making DNA and fuse with adjacent myoblasts to produce extended multicellular myotubes. DNA synthesis and nuclear division are not seen in multinucleated myotubes. After fusion, the myotubes begin to...