Muscle differentiation and macromolecular synthesis

摘要: Cytodifferentiation of skeletal muscle has been studied in cell cultures derived from leg 12-day chicken embryos. Myogenesis culture closely simulates myogenesis vivo, but is more highly synchronized. Massive fusion occurs control between the second and third days vitro, during which time most myoblasts are swept into syncytia. On successive days, syncytia mature cross-striated fibers, progressively overgrown by fibroblastic cells. Myosin-containing cells can be detected at any immunofluorescence, myosin measured quantitative immunological precipitation as early 3 a few hours after fusion. Myosin increases over next this reflected rate incorporation labeled amino acids immunologically precipitable myosin. Creatine kinase, assayed spectrophotometrically linked dehydrogenase reactions, shows similar pattern: measurable rapidly increasing activity That increase creatine kinase strictly function multinuclear demonstrated experiments mononuclear population drastically reduced treatment with 5-fluorodeoxyuridine shortly synthesis not detectable prevented fusing growth 5-bromo-deoxyuridine, low levels have demonstrated. Newly formed fibers incorporate precursors RNA lower rates than do The relationship change to formation proteins remains obscure.