牦牛Cygb基因的克隆及序列分析
Cloning and sequence analysis of cytoglobin gene in Yak

【目的】对牦牛Cygb基因进行克隆与序列分析，为进一步深入研究Cygb基因在牦牛对低氧环境适应性中的作用提供理论基础。【方法】参照GenBank中牛的Cygb基因序列设计引物，提取牦牛肝组织RNA，以反转录合成的cDNA为模版，克隆牦牛Cygb基因并进行测序，运用生物信息学软件对所得序列进行分析。【结果】牦牛Cygb基因编码区全长573 bp，编码190个氨基酸，编码产物分子质量21.5 ku，理论等电点为6.61。蛋白预测表明，Cygb编码蛋白整体表现为亲水性，蛋白质的二级结构主要由α螺旋及延伸链构成。同源性分析表明，11条序列当中牦牛与牛、绵羊等物种具有较高的同源性，在系统发育树中距离最近，其中牦牛与牛的同源性最高，达到99.0%。【结论】克隆到573 bp的牦牛Cygb基因编码区全长序列，该序列在哺乳动物中具有很高的保守性。
【Objective】This study cloned and analysed sequence of yak cytoglobin gene to improve the further study of Cygb gene.【Method】Based on the cygb gene sequence of bovine in GenBank,primers were designed to clone Cygb gene from yak.RNA from yak liver was extracted and cDNA synthesized by reverse transcription reaction was used as cloning template.Then the Cygb gene was cloned and sequenced.【Result】The length of the cloned Cygb cDNA was 573 bp with a peptide of 190 amino acids,the molecular weight of 21.5 ku and pI of 6.61.Protein prediction showed that Cygb protein was hydrophilic and the secondary structure of its protein were mainly alpha helix and extended strand.Sequence homology analysis shows that yak had higher homology with Bos taurus,Ovis aries and other mammals among the 11 sequences.The gene sequence of yak and Bos taurus had the highest homology of 99.0%.【Conclusion】The Cygb cDNA (573 bp) was cloned and its sequence was very conservative in mammals