Fetal myosin heavy chains in regenerating muscle
Fetal myosin heavy chains in regenerating muscle
复制标题
再生肌肉中的胎儿肌球蛋白重链
作者：
S. Sartore;L. Gorza;S. Schiaffino
有几条证据表明，在发育中的肌肉中存在一类独特的肌球蛋白1 -10。Whalen等人9最近使用各种生物化学和免疫学方法提出，在大鼠肌肉发育中，两种肌球蛋白重链同工酶顺序出现，先于最终的成体肌球蛋白。目前还不清楚这些肌球蛋白是否只存在于发育中的快速肌肉中，或者它们是否也存在于发育中的慢速肌肉中。焦磷酸盐凝胶电泳研究表明，快收缩和慢收缩肌肉在发育早期合成相同的胎儿肌球蛋白同工酶5。针对成人快肌球蛋白和慢肌球蛋白的抗体的免疫细胞化学研究显示，胎儿肌球蛋白之间的肌球蛋白组成存在差异11，但这些发现的解释因这些抗体与胎儿异肌球蛋白的交叉反应而变得复杂9。我们已经使用了一种更直接的免疫细胞化学方法，以确定肌球蛋白类型目前在发展中的肌纤维。制备了牛胎肌球蛋白特异性抗体，并与大鼠胎肌球蛋白发生交叉反应。我们在这里报告，该抗体识别的胎儿肌球蛋白重链在胎儿和新生大鼠肌肉中显示出异质性纤维分布，在出生后发育过程中逐渐消失，并在再生肌肉中瞬时表达。
There are several lines of evidence for the existence of a distinct class of myosins in developing muscle1–10. Using various biochemical and immunological approaches, Whalen et al.9 recently suggested that two myosin heavy chain isozymes appear sequentially in rat muscle development, preceding the definitive adult myosins. It is unknown whether these myosins are present only in developing fast muscles or whether they also occur in developing slow muscles. Pyrophosphate gel electrophoresis studies have suggested that fast-twitch and slow-twitch muscles synthesize the same fetal myosin isozymes early in development5. Immunocytochemical studies with antibodies directed against adult fast and slow myosins show differences in myosin composition between fetal muscle fibres11 but interpretation of these findings is complicated by cross-reactions of these antibodies with fetal isomyosins9. We have used a more direct immunocytochemical approach to identify the myosin types present in developing muscle fibres. An antibody specific for bovine fetal myosin and cross-reactive with rat fetal myosin has been prepared. We report here that the fetal myosin heavy chains recognized by this antibody show a heterogeneous fibre distribution in fetal and neonatal rat muscle, disappear progressively during postnatal development and are transiently expressed in regenerating muscle.