Jin J P
Department of Medical Biochemistry, University of Calgary Faculty of Medicine, Alberta, Canada.
Biochem Biophys Res Commun. 1996 Aug 23;225(3):883-9. doi: 10.1006/bbrc.1996.1267.
An alternative RNA splicing-generated cardiac troponin T (cTnT) isoform switching has been found during both avian and mammalian heart development. The present study demonstrates that the mouse cTnT isoform switching is approximately 10 days earlier than that in rat during perinatal heart development. The mouse cTnT isoform switching is also approximately 10 days earlier than the transcriptionally regulated troponin I (TnI) isoform switching, a transition that showed similar timing during mouse and rat heart development. In addition, synchronized cTnT and TnI switches are observed during both rat and chicken heart development. More interestingly, the expression of cTnT in both mouse and rat neonatal skeletal muscles showed an isoform transition pattern synchronized with the cTnT isoform switching in the neonatal heart of the corresponding species. The results suggest that the alternative RNA splicing-generated cTnT isoform switching during development is (a) not a direct response to the functional changes in perinatal myocardium and (b) not a restricted regulation in the heart, but is controlled by a species-specific programming that is synchronized in developing cardiac and skeletal muscles.
在鸟类和哺乳动物心脏发育过程中均发现了一种由RNA可变剪接产生的心肌肌钙蛋白T（cTnT）亚型转换。本研究表明，在围产期心脏发育过程中，小鼠cTnT亚型转换比大鼠早约10天。小鼠cTnT亚型转换也比转录调控的肌钙蛋白I（TnI）亚型转换早约10天，后者在小鼠和大鼠心脏发育过程中具有相似的转换时间。此外，在大鼠和鸡心脏发育过程中均观察到cTnT和TnI的同步转换。更有趣的是，小鼠和大鼠新生骨骼肌中cTnT的表达呈现出与相应物种新生心脏中cTnT亚型转换同步的亚型转换模式。结果表明，发育过程中由RNA可变剪接产生的cTnT亚型转换（a）不是对围产期心肌功能变化的直接反应，（b）不是心脏特有的调控，而是由一种在发育中的心脏和骨骼肌中同步的物种特异性程序控制。
