Myofibrillogenesis visualized in living embryonic cardiomyocytes
Myofibrillogenesis visualized in living embryonic cardiomyocytes
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DOI：
10.1073/pnas.94.17.9493
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发表时间：
1997-08-19
影响因子：
11.1
通讯作者：
Sanger, JW
中科院分区：
文献类型：
--
作者：
Dabiri, GA;Turnacioglu, KK;Sanger, JW
在培养的活心肌细胞中观察到肌原纤维形成，所述心肌细胞用表达与Z带蛋白α-辅肌动蛋白连接的绿色荧光蛋白（GFP）的质粒转染。该荧光蛋白的表达为含有α-辅肌动蛋白的结构提供了体内标记。GFP-α-辅肌动蛋白融合蛋白掺入Z带、闰盘和附着斑中，以及掺入点状聚集体中。或Z-小体，被认为是Z-带的前体。在培养物中对活细胞数天的观察使我们能够测试先前基于对固定细胞的研究而提出的肌原纤维组装的几种理论的方面。在心肌细胞的扩展边缘从头形成的细原纤维，称为前肌原纤维，含有点状浓度的α-辅肌动蛋白，称为Z-小体，随着时间的延长，相邻的肌原纤维和Z体融合，在Z体线性排列的胞质区域形成成熟的肌原纤维和Z带，这些新的肌原纤维在其Z带处与现有的肌原纤维对齐，形成跨越伸展细胞长度的肌原纤维，这些结果与假设在细胞膜附近从头形成的原纤维是前肌原纤维的模型一致，即，成熟肌原纤维的前体。
Myofibril formation was visualized in cultured live cardiomyocytes that were transfected with plasmids expressing green fluorescent protein (GFP) linked to the Z-band protein, alpha-actinin, The expression of this fluorescent protein provided an in vivo label for structures containing alpha-actinin, The GFP-alpha-actinin fusion protein was incorporated into Z-bands, intercalated discs, and attachment plaques, as well as into the punctate aggregates, or Z-bodies, that are thought to be the precursors of Z-bands, Observations of live cells over several days in culture permitted us to test aspects of several theories of myofibril assembly that had been proposed previously based on the study of fixed cells, Fine fibrils, called premyofibrils, that formed de novo at the spreading edges of cardiomyocytes, contained punctate concentrations of alpha-actinin, termed Z-bodies, The punctate Z-bodies grew and aligned with Z-bodies in adjacent fibrils, With increasing time, adjacent fibrils and Z-bodies appeared to fuse and form mature myofibrils and Z-bands in cytoplasmic regions where the linear arrays of Z-bodies had been, These new myofibrils became aligned with existing myofibrils at their Z-bands to form myofibrils that spanned the length of the spread cell, These results are consistent with a model that postulates that the fibrils that form de novo near the cell membrane are premyofibrils-i.e., the precursors of mature myofibrils.