Identification and characterization of troponin genes in Locusta migratoria
Identification and characterization of troponin genes in Locusta migratoria
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飞蝗肌钙蛋白基因的鉴定和表征
DOI：
10.1111/imb.12644
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发表时间：
2020
影响因子：
2.6
通讯作者：
Li X. -D.
中科院分区：
文献类型：
--
作者：
Liang H. -F.;Li J.;Li X. -D.
肌钙蛋白复合体由肌钙蛋白C(TpnC)、肌钙蛋白I(TpnI)和肌钙蛋白T(TpnT)三个亚基组成，调节横纹肌的收缩。我们发现蝗虫基因组中有一个TpnT基因(LmTpnT)、一个TpnI基因(LmTpnI)和三个TpnC基因(LmTpnC1、LmTpnC2和LmTpnC3)。通过选择性剪接，LmTpnT和LmTpnI可能分别编码两种和八种异构体。飞跃肌和跳跃肌表达相同的LmTpnT亚型，但表达不同的LmTpnC和LmTpnI亚型。LmTpnC2和LmTpnC3都含有EF-Hand II和IV中钙结合所必需的高度保守的残基，因此属于双位点异构体。突变和酪氨酸荧光光谱分析表明，LmTpnC1Ef-Hand II和Ef-Hand IV均可作为钙结合位点。因此，三种LmTpnC亚型均属于双位点亚型。这与具有异步飞行肌肉的昆虫的情况相反，后者既表达TpnC的一个位点异构体，也表达两个位点的异构体。这些结果表明，昆虫异步性飞行肌肉的起源与TpnC单位点亚型的出现有关。
Troponin complex comprises three subunits, namely troponin C (TpnC), troponin I (TpnI) and troponin T (TpnT), and regulates the contraction of striated muscle. We found that the locust Locusta migratoria genome has one TpnT gene (LmTpnT), one TpnI gene (LmTpnI) and three TpnC genes (LmTpnC1, LmTpnC2 and LmTpnC3). Through alternative splicing, LmTpnT and LmTpnI potentially encode two and eight isoforms, respectively. The flight muscle and the jump muscle of L. migratoria express an identical LmTpnT isoform, but different LmTpnC isoforms and LmTpnI isoforms. LmTpnC2 and LmTpnC3 both contain highly conserved residues essential for calcium binding in the EF‐hand II and IV, thus belonging two‐site isoform. LmTpnC1 contains non‐conserved substitutions in the EF‐hand II and all highly conserved residues for calcium binding in the EF‐hand IV. Mutagenesis and tyrosine fluorescence spectroscopic analysis show that both the EF‐hand II and IV of LmTpnC1 can serve as calcium‐binding site. Therefore, all three LmTpnC isoforms belong to two‐site isoform. This is in contrast to the situation in the insect with asynchronous flight muscle, which expresses both one‐site isoform and two‐site isoform of TpnC. Those results suggest that the origination of insect asynchronous flight muscle is associated with the emergence of one‐site isoform of TpnC.