Hodgson P A, Leaver M J, George S G, MacLean D W, Hastings K E
N.E.R.C. Unit of Aquatic Biochemistry, School of Natural Sciences University of Stirling, UK.
Biochim Biophys Acta. 1996 May 2;1306(2-3):142-6. doi: 10.1016/0167-4781(96)00033-4.
By cDNA cloning and 5'-RACE analysis we characterised a Clupea harengus troponin I mRNA expressed in larvae and in adult white (fast) muscle, but not in red (slow) or cardiac muscle. The mRNA encodes a TnI protein of the short chain length (176 residues) N-terminally truncated type previously observed only in tetrapod skeletal muscles. Despite its expression specificity the herring TnI does not particularly resemble the tetrapod fast skeletal muscle isoform in sequence but appears to be outside of the tetrapod TnIfast/Tnslow/TnIcardiac isoform family. Surprisingly, the actin/TnC-binding sequence resembles that of arthropod, rather than tetrapod vertebrate, troponin I's and has, besides, unique features not seen in any other troponin I's, vertebrate or invertebrate.
通过cDNA克隆和5'-RACE分析，我们鉴定了一种在鲱鱼幼虫和成体白色（快）肌肉中表达，但在红色（慢）肌肉或心肌中不表达的肌钙蛋白I mRNA。该mRNA编码一种短链长度（176个残基）的N端截短型TnI蛋白，这种类型之前仅在四足动物的骨骼肌中观察到。尽管鲱鱼TnI具有表达特异性，但其序列与四足动物的快骨骼肌亚型并不特别相似，似乎不在四足动物TnIfast/Tnslow/TnIcardiac亚型家族中。令人惊讶的是，肌动蛋白/TnC结合序列类似于节肢动物而非四足动物脊椎动物的肌钙蛋白I，此外，还具有在任何其他脊椎动物或无脊椎动物的肌钙蛋白I中未见的独特特征。
