Myofibrillogenesis in the first cardiomyocytes formed from isolated quail precardiac mesoderm.

摘要: De novo assembly of myofibrils was investigated in explants precardiac mesoderm from quail embryos to address a controversy about different models myofibrillogenesis. The sequential expression sarcomeric components visualized double- and triple-stained before, during, just after the first cardiomyocytes began beat. In stage 6 embryos, cultured for 10 h, ectoderm, endoderm, displayed arrays stress fibers with alternating bands nonmuscle isoforms α-actinin myosin IIB. With increasing time culture, cells contained fibrils composed actin, IIB, α-actinin. Several hours later, before beating occurred, both muscle II localized some cells. Concentrations as thin bundles, dispersed cytoplasm, often overlapping one another, progressed small, aligned A-band-sized aggregates. amount decreased dramatically when Z-bands formed, became organized into A-bands, beating. changes protein composition developing supports model myofibrillogenesis which begins premyofibrils progresses through nascent mature myofibrils.