高原牦牛肺脏iNOS基因克隆及序列分析

Cloning and sequence analysis of iNOS gene in lung of plateau yak

为了阐明高原牦牛诱导型一氧化氮合酶(inducible NOS, iNOS)在基因水平上对肺脏低氧适应的作用,试验以高原牦牛为研究对象,采用PCR扩增方法克隆了高原牦牛iNOS基因cDNA序列,并对iNOS基因的CDS序列及其编码的蛋白结构进行生物信息学分析。结果表明:高原牦牛iNOS基因的CDS序列全长为3 471 bp,共编码1 156个氨基酸;iNOS蛋白分子质量约为131.03 ku,信号肽预测显示为胞内蛋白,其氨基酸序列具有多个功能域位点,在iNOS蛋白的二级结构中,α-螺旋占37.28%、β-转角占7.27%、无规则卷曲占37.46%、延伸链占17.99%,且核苷酸序列与黄牛、马、犬、人和小鼠的同源性分别为99.45%、78.05%、85.81%、80.84%和80.73%,氨基酸序列与黄牛、马、犬、人和小鼠的同源性分别为99.57%、76.28%、84.18%、79.67%和80.54%。说明iNOS基因在进化过程中相对保守,其编码的氨基酸序列在高原牦牛与黄牛间具有较高的一致性,但与其他物种相比一致性较低。

In order to study the effect of inducible nitric oxide synthase ( iNOS) on hypoxia adaptation in lung of plateau yak,the Qinghai-Tibet plateau yaks( Bos grunniens) was selected as the research object. The CDS sequences of iNOS gene from plateau yak was cloned successfully by using PCR amplification technology. The sequence and the protein structure of iNOS were analysed. The results showed that the length of iNOS CDS of plateau yak was 3 471 bp and encoding 1 156 amino acid. The molecular mass of iNOS protein was about 131. 03 ku. In the secondary structure of iNOS protein,α-helix accounted for 37. 28%,β-bend accounted for 7. 27%,random coil accounted for 37. 46%,and extended chain accounted for 17. 99%.The signal peptide was predicted to be an intracellular protein,and its amino acid sequence had multiple function-al domains. The nucleotide sequence homology of gene in the yak lungs compared with cattle,horse,dog,human and mouse were 99. 45%, 78. 05%,85. 81%,80. 84% and 80. 73%,respectively,the sequence homology of amino acids were 99. 57%,76. 28%,84. 18%,79. 67%, 80. 54%,respectively. The results indicated that the gene of iNOS is relatively conservative in evolution and the amino acids of plateau yak have high homology with cattle and low homology with other animals.