Three alternatively spliced mouse slow skeletal muscle troponin T isoforms: conserved primary structure and regulated expression during postnatal development
Three alternatively spliced mouse slow skeletal muscle troponin T isoforms: conserved primary structure and regulated expression during postnatal development
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DOI：
10.1016/s0378-1119(98)00214-5
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发表时间：
1998-07-03
期刊：
影响因子：
3.5
通讯作者：
Huang, QQ
中科院分区：
文献类型：
--
作者：
Jin, JP;Chen, AH;Huang, QQ
我们克隆并测序了编码小鼠慢骨骼肌肌钙蛋白T （sTnT）的全长cdna。通过Western blotting、逆转录聚合酶链反应和cDNA克隆/表达分析，鉴定了不同nh2末端初级结构的两个高M-r亚型和一个低M-r sTnT亚型。与在人类sTnT中发现的编码11个氨基酸酸性片段的5'-可选外显子一起，研究结果揭示了一种新的可选剪接途径，可以包括或排除一个3碱基片段，从而产生具有nh2末端电荷变化的额外sTnT异构体。超越系统发育差异，sTnT的初级结构在哺乳动物和鸟类之间的保守性优于来自同一物种的心脏、快速和骨骼肌的tnt。Western blot结果显示，sTnT在出生后骨骼肌发育过程中有四种表达模式：(1)在小鼠咬肌中降低至不可检测水平，(2)在羊咬肌中增加成为唯一的TnT，(3)羊膈肌中总水平和低M-r亚型比例增加，(4)羊腓肠肌中总水平和高低M-r亚型比例无显著变化。sTnT高度保守的初级结构、纤维类型特异性和发育调控表达表明，这一TnT基因家族中尚未被研究的成员具有重要的生理意义。(C) 1998 Elsevier Science B.V.版权所有
We have cloned and sequenced full-length cDNAs encoding mouse slow skeletal muscle troponin T (sTnT). Alternative mRNA splicing-generated two high M-r isoforms and one low M-r sTnT isoform differing in the NH2-terminal primary structure have been identified by Western blotting, reverse transcription-polymerase chain reaction and cDNA cloning/expression analyses. Together with a 5'-alternative exon that was also found in human sTnT encoding an 11-amino-acid acidic segment, the results revealed a novel alternative splicing pathway to include or exclude a three-base segment to generate additional sTnT isoforms with NH2-terminal charge variations. Overriding the phylogenetic divergence, primary structure of sTnT is better conserved between mammalian and avian species than that of cardiac, fast and skeletal muscle TnTs from one species. Western blots demonstrate four expression patterns of sTnT during postnatal skeletal muscle development: (1) a decrease to a non-detectable level in mouse masseter, (2) an increase to become the sole TnT in sheep masseter, (3) an increase of the total level as well as the proportion of the low M-r isoform in sheep diaphragm and, (4) no significant change in total level or high/low M-r isoform ratio in sheep gastrocnemius. The highly conserved primary structure and fiber type-specific and developmentally regulated expression of sTnT indicate a physiological importance of this under-studied member of the TnT gene family. (C) 1998 Elsevier Science B.V. All rights reserved.