摘要：

为揭示MYL2基因在牦牛肌肉发育与高原适应性中的作用机制,探索其对牦牛肉品质和生产性能的潜在影响,对帕米尔牦牛MYL2基因进行了克隆与组织表达分析。通过克隆其编码区(CDS)并进行生物学功能预测和不同组织表达谱分析,进一步明确MYL2基因的功能特征。采用实时荧光定量PCR(RT-qRCR)技术,对帕米尔牦牛的心脏、肝脏、脾脏、肺脏、肾脏、胰腺以及背最长肌进行MYL2基因表达水平的定量。结果表明,帕米尔牦牛MYL2基因CDS区的长度为501 bp,编码166个氨基酸。同源性比对发现,帕米尔牦牛MYL2基因与野牦牛的亲缘关系最近,相似度可达到100%,与鸡的亲缘关系最远。蛋白分析结果发现,其蛋白分子式C₈₄₂H₁₃₁₃N₂₁₉O₂₆₁S₇,分子质量为18.904 42 ku,理论等电点为4.831;不稳定系数为28.3,表明该蛋白属于稳定蛋白;该蛋白存在1个 N-糖基化潜在位点和15处潜在磷酸化位点;此外,该蛋白结构中不包含跨膜结构和信号肽,主要定位于细胞质膜和细胞壁上;二级结构主要由93个α-螺旋(占比56.02%)、60个无规则卷曲(占比7.83%)和13个β-折叠(占比36.14%)构成。RT-qPCR结果表明,MYL2基因在帕米尔牦牛心脏和背最长肌组织中表达量极显著高于其他组织,提示该基因可能在心肌功能维持与骨骼肌生长过程中发挥关键调控作用。结合蛋白功能预测结果推测,MYL2基因可能通过调控肌肉结构蛋白的表达,参与牦牛心肌与骨骼肌的发育,有助于牦牛在高寒低氧环境中维持良好的运动与产热能力,增强高原适应性。

关键词: 帕米尔牦牛, MYL2基因, 基因克隆, 生物信息学

Abstract:

To elucidate the role of the MYL2 gene in muscle development and high-altitude adaptation in yak,and to explore its potential impact on meat quality and production performance,this study conducted cloning and tissue expression analysis of the MYL2 gene in Pamir yak.By cloning its coding sequence(CDS)and performing bioinformatics-based functional prediction and tissue-specific expression profiling,the functional characteristics of the MYL2 gene were further clarified.Additionally,it seeks to analyze and explore the structure and function of the MYL2 gene.Real-time quantitative PCR(RT-qPCR)technology was employed to quantify the expression levels of the MYL2 gene in various tissues of the Pamir yak,including the heart,liver,spleen,lung,kidney,pancreas,and longissimus dorsi muscle.The results indicated that the coding sequence(CDS)length of the Pamir yak MYL2 gene was 501 bp,which encoded a protein of 166 amino acids.Comparative homology analysis revealed that the MYL2 gene of Pamir yak shared the closest genetic relationship with that of the wild yak,exhibiting a similarity of 100%,while the most distant genetic relationship was observed with the chicken.The protein analysis results indicated that the molecular formula of the protein was C₈₄₂H₁₃₁₃N₂₁₉O₂₆₁S₇,with a molecular mass of 18.904 42 ku and a theoretical isoelectric point of 4.831.The instability index was measured at 28.3,suggesting that the protein was stable.Additionally,the protein contained one N-glycan modification potential site and 15 potential phosphorylation sites.Furthermore,its structure did not exhibit a transmembrane domain or signal peptide,and it was primarily localized in the cytoplasmic membrane and cell wall.The secondary structure was predominantly composed of 93 α-helices(56.02%),60 random coils(7.83%),and 13 β-sheets(36.14%).RT-qPCR results showed that MYL2 gene expression was extremely significantly higher in the heart and longissimus dorsi muscle of Pamir yak compared to other tissues,suggesting that this gene may play a key regulatory role in maintaining cardiac function and promoting skeletal muscle growth.Based on protein function prediction,MYL2 is likely involved in the development of cardiac and skeletal muscles by regulating the expression of muscle structural proteins,thereby contributing to the maintenance of locomotor capacity and thermogenic performance under cold,hypoxic plateau conditions.

Key words: Pamir yak, MYL2 gene, Gene cloning, Bioinformatics

中图分类号: 

• S823.85