Molecular structure and developmental expression of three muscle-type troponin T genes in zebrafish
Molecular structure and developmental expression of three muscle-type troponin T genes in zebrafish
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DOI：
10.1002/dvdy.10305
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发表时间：
2003-06-01
影响因子：
2.5
通讯作者：
Tsai, HJ
中科院分区：
文献类型：
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作者：
Hsiao, CD;Tsai, WY;Tsai, HJ
肌钙蛋白T（Tnnt）是一种肌钙蛋白组分，与原肌球蛋白相互作用，对横纹肌收缩的调节至关重要。为了深入了解Tnnt基因（Tnnt）在低等脊椎动物中的分子进化和发育调控，对斑马鱼Tnnt 1（慢Tnnt）、Tnnt 2（心脏Tnnt）和Tnnt 3 B（快Tnnt亚型B）进行了研究。斑马鱼Tnnt 1，Tnnt 2和Tnnt 3b的多肽在中央原肌球蛋白和C-末端肌钙蛋白I结合结构域中是保守的。然而，在Tnnt 1和Tnnt 2的多肽中，N-末端高变区高度延伸并且富含谷氨酸，但Tnnt 3b不。Tnnt 2和Tnnt 3b含有内含子，而Tnnt 1不含内含子。在发育过程中，在Tnnt 2中检测到大到小的选择性剪接变体，但在Tnnt 1或Tnnt 3中未检测到。整体原位杂交结果显示，Tnnt 1和Tnnt 2分别在胚胎早期（受精后10 h，hpf）和心脏期（14 hpf）被激活，而Tnnt 3b直到胚胎中期（18 hpf）才被激活。Tnnt 2和Tnnt 3b的表达是心脏和快肌特异性的，但Tnnt 1在慢肌和快肌中都有表达。我们建议，三个，不同的，肌肉型TnNT进化后，鱼类和后口无脊椎动物的分歧。在斑马鱼中，Tnnt在体节发生和心脏发生过程中的发育调控比四足动物更受限制和简单。这些新发现可能为脊椎动物Tnnt的发育调控和分子进化提供新的见解。Developmental Dynamics 227：266-279，2003. (C)2003 Wiley-Liss，Inc.
Troponin T (Tnnt), a troponin component, interacts with tropomyosin and is crucial to the regulation of striated muscle contraction. To gain insight into the molecular evolution and developmental regulation of Tnnt gene (Tnnt) in lower vertebrates, zebrafish Tnnt1 (slow Tnnt), Tnnt2 (cardiac Tnnt), and Tnnt3b (fast Tnnt isoform b) were characterized. The polypeptides of zebrafish Tnnt1, Tnnt2, and Tnnt3b were conserved in the central tropomyosin- and C-terminal troponin I-binding domains. However, the N-terminal hypervariable regions were highly extended and rich in glutamic acid in polypeptides of Tnnt1 and Tnnt2, but not Tnnt3b. The Tnnt2 and Tnnt3b contain introns, whereas Tnnt1 is intron-free. During development, large to small, alternatively spliced variants were detected in Tnnt2, but not in Tnnt1 or Tnnt3. Whole-mount in situ hybridization showed zebrafish Tnnt1 and Tnnt2 are activated during early somitogenesis (10 hr postfertilization, hpf) and cardiogenesis (14 hpf), respectively, but Tnnt3b is not activated until middle somitogenesis (18 hpf). Tnnt2 and Tnnt3b expression was cardiac- and fast-muscle specific, but Tnnt1 was expressed in both slow and fast muscles. We propose that three, distinct, muscle-type Tnnt evolved after the divergence of fish and deuterostome invertebrates. In zebrafish, the developmental regulation of Tnnt during somitogenesis and cardiogenesis is more restricted and simpler than in tetrapods. These new findings may provide insight into the developmental regulation and molecular evolution of vertebrate Tnnt. Developmental Dynamics 227: 266-279, 2003. (C) 2003 Wiley-Liss, Inc.