Abstract：
Tropomyosin 3 (TPM3) plays a significant role as a regulatory protein in muscle contraction, affecting the growth and development of skeletal muscles. Despite its importance, limited research has been conducted to investigate the influence of TPM3 on bovine skeletal muscle development. Therefore, this study revealed the role of TPM3 in bovine myoblast growth and development. This research involved conducting a thorough examination of the Qinchuan cattle TPM3 gene using bioinformatics tools to examine its sequence and structural characteristics. Furthermore, TPM3 expression was evaluated in various bovine tissues and cells using quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that the coding region of TPM3 spans 855 bp, with the 161st base being the T base, encoding a protein with 284 amino acids and 19 phosphorylation sites. This protein demonstrated high conservation across species while displaying a predominant α-helix secondary structure despite being an unstable acidic protein. Notably, a noticeable increase in TPM3 expression was observed in the longissimus dorsi muscle and myocardium of calves and adult cattle. Expression patterns varied during different stages of myoblast differentiation. Functional studies that involved interference with TPM3 in Qinchuan cattle myoblasts revealed a very significantly decrease in S-phase cell numbers and EdU-positive staining (P < 0.01), and disrupted myotube morphology. Moreover, interference with TPM3 resulted in significantly (P < 0.05) or highly significantly (P < 0.01) decreased mRNA and protein levels of key proliferation and differentiation markers, indicating its role in the modulation of myoblast behavior. These findings suggest that TPM3 plays an essential role in bovine skeletal muscle growth by influencing myoblast proliferation and differentiation. This study provides a foundation for further exploration into the mechanisms underlying TPM3-mediated regulation of bovine muscle development and provides valuable insights that could guide future research directions as well as potential applications for livestock breeding and addressing muscle-related disorders.
摘要：
原肌球蛋白3(TPM3)作为调节蛋白在肌肉收缩中发挥重要作用,影响骨骼肌的生长和发育。尽管它很重要,已经进行了有限的研究来研究TPM3对牛骨骼肌发育的影响。因此,本研究揭示了TPM3在牛成肌细胞生长发育中的作用。这项研究涉及使用生物信息学工具对秦川牛TPM3基因进行全面检查，以检查其序列和结构特征。此外，使用定量实时聚合酶链反应(qRT-PCR)在各种牛组织和细胞中评估TPM3表达。结果表明,TPM3的编码区跨越855bp,第161个基地是T基地，编码具有284个氨基酸和19个磷酸化位点的蛋白质。尽管是不稳定的酸性蛋白，但该蛋白在物种中表现出高度保守性，同时表现出主要的α-螺旋二级结构。值得注意的是,在小牛和成年牛的背最长肌和心肌中观察到TPM3表达显着增加。在成肌细胞分化的不同阶段，表达模式有所不同。对秦川牛成肌细胞中TPM3干扰的功能研究显示，S期细胞数量和EdU阳性染色非常显着减少（P<0.01），和破坏的肌管形态。此外，干扰TPM3显著(P<0.05)或极显著(P<0.01)降低关键增殖和分化标志物的mRNA和蛋白水平,表明其在调节成肌细胞行为中的作用。这些发现表明TPM3通过影响成肌细胞的增殖和分化在牛骨骼肌生长中起着至关重要的作用。这项研究为进一步探索TPM3介导的牛肌肉发育调控机制奠定了基础，并提供了有价值的见解，可以指导未来的研究方向以及在家畜育种和解决肌肉相关疾病方面的潜在应用。
