Vivarelli E, Brown W E, Whalen R G, Cossu G
Istituto di Istologia ed Embriologia Generale, l'Università di Roma, Italy.
J Cell Biol. 1988 Dec;107(6 Pt 1):2191-7. doi: 10.1083/jcb.107.6.2191.
The developmental pattern of slow myosin expression has been studied in mouse embryos from the somitic stage to the period of secondary fiber formation and in myogenic cells, cultured from the same developmental stages. The results obtained, using a combination of different polyclonal and monoclonal antibodies, indicate that slow myosin is coexpressed in virtually all the cells that express embryonic (fast) myosin in somites and limb buds in vivo as well as in culture. On the contrary fetal or late myoblasts (from 15-d-old embryos) express in culture only embryonic (fast) myosin. At this stage, muscle cells in vivo, as already shown (Crow, M.T., and F.A. Stockdale. 1986. Dev. Biol. 113:238-254; Dhoot, G.K. 1986. Muscle & Nerve. 9:155-164; Draeger, A., A.G. Weeds, and R.B. Fitzsimons. 1987. J. Neurol. Sci. 81:19-43; Miller, J.B., and F.A. Stockdale. 1986. J. Cell Biol. 103:2197-2208), consist of primary myotubes, which express both myosins, and secondary myotubes, which express preferentially embryonic (fast) myosin. Under no circumstance neonatal or adult fast myosins were detected. Western blot analysis confirmed the immunocytochemical data. These results suggest that embryonic myoblasts in mammals are all committed to the mixed embryonic-(fast) slow lineage and, accordingly, all primary fibers express both myosins, whereas fetal myoblasts mostly belong to the embryonic (fast) lineage and likely generate fibers containing only embryonic (fast) myosin. The relationship with current models of avian myogenesis are discussed.
已对从体节期到次级纤维形成期的小鼠胚胎以及从相同发育阶段培养的成肌细胞中慢肌球蛋白表达的发育模式进行了研究。使用不同的多克隆和单克隆抗体组合获得的结果表明，在体内以及培养条件下，慢肌球蛋白在体节和肢芽中几乎所有表达胚胎型（快）肌球蛋白的细胞中共同表达。相反，胎儿或晚期成肌细胞（来自15日龄胚胎）在培养物中仅表达胚胎型（快）肌球蛋白。在这个阶段，如已表明的那样（Crow, M.T., 和F.A. Stockdale. 1986. 《发育生物学》. 113:238 - 254；Dhoot, G.K. 1986. 《肌肉与神经》. 9:155 - 164；Draeger, A., A.G. Weeds, 和R.B. Fitzsimons. 1987. 《神经科学杂志》. 81:19 - 43；Miller, J.B., 和F.A. Stockdale. 1986. 《细胞生物学杂志》. 103:2197 - 2208），体内的肌肉细胞由既表达两种肌球蛋白的初级肌管和优先表达胚胎型（快）肌球蛋白的次级肌管组成。在任何情况下都未检测到新生儿或成人的快肌球蛋白。蛋白质免疫印迹分析证实了免疫细胞化学数据。这些结果表明，哺乳动物的胚胎成肌细胞都倾向于混合的胚胎型 - （快）慢谱系，因此，所有初级纤维都表达两种肌球蛋白，而胎儿成肌细胞大多属于胚胎型（快）谱系，可能产生仅含有胚胎型（快）肌球蛋白的纤维。本文还讨论了与当前鸟类肌生成模型的关系。
