绵羊LDHβ基因的生物信息学分析及其在不同剩余采食量绵羊肝脏和肌肉组织中的表达

Bioinformatics analysis of ovine LDHβ gene and its expression in liver and muscle of sheep with different residual feed intake

【目的】为鉴定绵羊乳酸脱氢酶β(lactate dehydrogenase B,LDHβ)基因的分子特征,研究其在不同剩余采食量绵羊肝脏和肌肉组织中的表达差异.【方法】测定了137只‘湖羊’公羔的剩余采食量(residual feed intake,RFI),按RFI进行排序,分别筛选出RFI最高(high-residual feed intake,H-RFI)和RFI最低(low-residual feed intake,L-RFI)的羊各15只,屠宰后,采集肝脏和肌肉组织,利用Q-PCR技术检测绵羊LDHβ基因分别在H-RFI和L-RFI羊肝脏和肌肉中表达量,并利用生物信息学软件构建了该基因的系统进化树和预测其结构与功能.【结果】绵羊LDHβ基因开放阅读框(open reading frame,ORF)为1 005bp,编码334个氨基酸,其蛋白质分子质量为36 479.43U,理论等电点为6.40.绵羊LDHβ基因与山羊的亲缘关系较近,其次为牛,序列同源性高.功能结构域预测结果显示,该基因编码产物在内质网中参与辅酶因子生物合成的可能性最高.Q-PCR结果显示,绵羊LDHβ-mRNA基因在L-RFI羊肝脏和肌肉中表达量均显著低于H-RFI羊(P<0.01).【结论】绵羊LDHβ基因作为能量代谢的关键酶参与绵羊饲料效率的调控.

【Objective】In order to identify the molecular characteristics of LDHβ （lactate dehydrogenase B）gene,the difference in expression of LDHβ gene was researched in liver and muscle tissues of sheep with different residual feed intake.【Method】Residual feed intake（RFI）of 137 Hu sheep were determined,according to the sort of RFI,selecting 15 lambs with highest（High-residual feed intake,H-RFI）and lowest（Low-residual feed intake,L-RFI）RFI,respectively.After slaughter,the liver and muscle tissue samples were collected and Q-PCR was applied to detect LDHβ gene expression in liver and muscle of H-RFI and LRFI and bioinformation software was used to construct ovine RARG gene phylogenetic tree and predict its protein structure and function.【Result】Open reading frame（ORF）of sheep LDHβ gene was 1005 bp,which encoded 334 amino acids with molecular weight of 36 479.43 Uand estimated isoelectric point（pI）of 6.4.Phylogenetic tree analysis showed that the ovine LDHβ gene had closer relationship with goat,followed by bos taurus,and the gene sequence among these species showed high homology.Prediction in function and structure indicated that the coding products of LDHβ had highest possibility of participating in biosynthesis of cofactors in endoplasmic reticulum.Q-PCR result displayed that the expression of ovine LDHβ mRNA in liver and muscle of L-RFI group was significantly lower than that in H-RFI group（P〈0.01）.【Conclusion】The ovine LDHβ gene involved in regulating the feed efficiency of sheep as a key energy metabolism enzyme.