摘要： 补体C1q （Complement 1q）蛋白由A、B、C 3条多肽链构成，在维护机体内环境稳定、氧化应激、糖脂代谢等过程发挥重要作用。为研究牦牛C1QA、C1QB、C1QC基因的分子特性及在不同组织中的表达水平，探讨该基因对牦牛高原适应性的影响，通过克隆获得牦牛C1QA、C1QB、C1QC基因的CDS区序列，分析其核苷酸序列相似性并构建系统进化树；利用在线软件进行功能预测分析；采用实时荧光定量PCR方法检测3个基因在牦牛心脏、肝脏、脾脏、肺脏和肾脏组织中的相对表达量。结果显示：C1QA、C1QB、C1QC基因CDS区全长分别为735，744，732 bp，分别编码244，247，243个氨基酸；3个基因编码的蛋白质均为稳定的亲水性蛋白，主要由甘氨酸（Gly）和脯氨酸（Pro）组成，含有C1Q结构域和信号肽，不存在跨膜结构域，属胞外蛋白；蛋白氨基酸序列中分别存在18，21，15个潜在的磷酸化位点，三者二级结构主要由无规则卷曲构成，比例分别为61.85%，63.97%，66.67%。荧光定量结果显示，C1QA、C1QB基因在肺脏、脾脏中表达量较高，极显著高于心脏、肝脏、肾脏组织（P <0.01），C1QC基因在肺脏的表达量极显著高于心脏、肝脏、脾脏、肾脏组织（P <0.01）。试验结果为深入研究C1QA、C1QB、C1QC基因在牦牛高原适应中的生理功能和调控机制提供了基础数据。

关键词: 牦牛, 补体C1q, 基因克隆, 组织表达, 功能预测

Abstract: Complement C1q(Complement 1q) protein consists of three polypeptide chains,A,B and C,which plays an important role in stabilization of homeostasis,oxidative stress,and glucose and lipid metabolism. The aim of this study was to clone the CDS of C1QA,C1QB and C1QC genes and detect their expression patterns in various tissues,and then explore the molecular mechanism of these genes in Yak high altitude adaptation. Total RNA were extracted from various tissues,including heart,liver,spleen,lung and kidney. The mRNA expression levels of C1QA,C1QB and C1QC genes were determined by Real-time PCR. The cDNA length of C1QA,C1QB and C1QC genes were 735,744 and 732 bp,which encoded 244,247 and 243 amino acids,respectively. Bioinformatics analysis found that C1QA,C1QB and C1QC were stable hydrophilic proteins,which dominated by glycine (Gly) and proline (pro). The C1QA,C1QB and C1QC contained C1Q domain,signal peptide,and without transmembrane domain,which distributed in extracellular region. There were 18,21 and 15 phosphorylation sites in the three protein sequence,respectively. For the secondary structure of the three proteins,they were mainly composed of irregular curls,and the proportions were 61.85%,63.97% and 66.67%,respectively. Furthermore,for the expression patterns of C1QA and C1QB,lung and spleen had higher expression levels than heart,liver and kidney (P <0.01),for C1QC, heart,liver,spleen and kidney had lower expression levels than lung(P <0.01). This study may provid basic data for the functional and molecular mechanism in Yak high altitude adaptation.

Key words: Yak, Complement C1q, Gene cloning, Tissue expression, Function prediction

中图分类号: 

• Q78

• S823