Babai F, Musevi-Aghdam J, Schurch W, Royal A, Gabbiani G
Département de Pathologie, Université de Montréal C.P. 6128, Succ. A Montréal, Québec, Canada.
Differentiation. 1990 Aug;44(2):132-42. doi: 10.1111/j.1432-0436.1990.tb00546.x.
Expression of vimentin, desmin, alpha-sarcomeric and alpha-smooth muscle actins in embryonic tissues of rat and mice was examined using an immunohistochemical approach. The results showed a similarity in the expression of desmin and alpha-actin isoforms (alpha-sr and alpha-sm) in skeletal muscle cells during murine feto-embryonic development. In the two species, coexpression of alpha-sr and alpha-sm actins has been observed in cardiomyoblasts, myotomal myoblasts and myotubes. The intensity of alpha-sm actin expression decreased during the terminal steps of myogenesis and disappeared completely in mature cardiomyocytes and myofibres. Desmin was expressed in all prefusion myoblasts (type 1 and 2 myoblasts), myotubes, and in myofibres. The appearance of desmin in myoblasts of somites preceded by a few hours the expression of the alpha-actins (alpha-sr and alpha-sm). Our study on vimentin expression, limited to rat embryos, revealed that somite premyoblasts expressed only vimentin, type 1 myoblasts expressed vimentin and desmin, and type 2 myoblasts (rhabdomyoblasts) expressed desmin and alpha-actins (alpha-sr and alpha-sm). Our study demonstrates the resemblance between feto-embryonic myogenesis and myogenic neoplastic differentiation: desmin appears before the alpha-actins in embryonic myoblasts, and can be considered as a marker of an initial step in myogenic differentiation. alpha-sm actin, considered as a striated muscle cell feto-embryonic actin, is expressed transiently in skeletal myoblasts and cardiomyoblasts during development and reappears during neoplastic transformation of skeletal muscle.
采用免疫组织化学方法检测了波形蛋白、结蛋白、α-肌节肌动蛋白和α-平滑肌肌动蛋白在大鼠和小鼠胚胎组织中的表达。结果显示，在小鼠胚胎发育过程中，结蛋白和α-肌动蛋白异构体（α-sr和α-sm）在骨骼肌细胞中的表达具有相似性。在这两个物种中，已观察到α-sr和α-sm肌动蛋白在成心肌细胞、体节成肌细胞和肌管中共表达。在肌生成的终末阶段，α-sm肌动蛋白的表达强度降低，并在成熟的心肌细胞和肌纤维中完全消失。结蛋白在所有融合前的成肌细胞（1型和2型成肌细胞）、肌管和肌纤维中均有表达。体节成肌细胞中结蛋白的出现比α-肌动蛋白（α-sr和α-sm）的表达早几个小时。我们对波形蛋白表达的研究仅限于大鼠胚胎，结果显示体节前成肌细胞仅表达波形蛋白，1型成肌细胞表达波形蛋白和结蛋白，2型成肌细胞（横纹肌母细胞）表达结蛋白和α-肌动蛋白（α-sr和α-sm）。我们的研究表明胚胎肌生成与肌源性肿瘤分化之间存在相似性：在胚胎成肌细胞中，结蛋白在α-肌动蛋白之前出现，可被视为肌源性分化初始阶段的标志物。α-sm肌动蛋白被认为是横纹肌细胞胚胎期肌动蛋白，在发育过程中在骨骼肌成肌细胞和成心肌细胞中短暂表达，并在骨骼肌肿瘤转化过程中再次出现。
