鲫鱼ghrelin基因的克隆和生物信息学分析

Cloning and bioinformatics analysis of ghrelin gene in Carassius auratus

从鲫鱼的肠道内提取总RNA,运用RT-PCR扩增ghrelin基因并测序,用生物信息学软件预测其结构,并构建系统进化树,探讨了鲫鱼ghrelin基因的生物学功能,为进一步研究该基因对鲫鱼摄食的影响奠定基础。结果显示,获得了长490bp的ghrelin基因(GenBank登录号为HM567312),其序列含有1个312bp的完整开放阅读框,编码103个氨基酸;ghrelin蛋白分子质量为11 519.48u,等电点为5.20,半衰期为1.20h,不稳定系数为31.29,总平均亲水性为0.727,疏水性为-2.900～2.856;1～26位氨基酸可能是信号肽序列;在ghrelin的分子序列中存在44处α螺旋富集区域,8处β折叠区域,集中于成熟肽部分,有43处无规则卷曲。系统进化树分析显示鲫鱼ghrelin基因与金鱼的进化距离最近。

The biological function of ghrelin gene in crucian carp was explored to provide a basis to study effect of the gene on appetite of crucian.The ghrelin gene was amplified from total RNA extracted from the crucian carp intestine by RT-PCR and sequenced and the structure and function of the protein encoded by the gene were investigated.The function of the ghrelin gene-encoded protein was predicted by the bioinformatics software and the phylogenetic tree of ghrelin gene was constructed by CLUSTALW software.In result,the amplified crucian carp ghrelin protein gene was 490 bp in length and submitted to GenBank（GenBank accession number：HM567312）.Bioinformatics analysis showed that the gene contained the complete coding sequence of ghrelin protein,which was 312 bp in size,encoded 103 amino acids.The crucian carp ghrelin was 11 519.48 u in molecular weight,5.20 in isoelectric point,about 1.20 hours in half-life,and 31.29 in instability index.The mean of hydropathicity of ghrelin protein was 0.727,while the hydrophobicity was between-2.900 and 2.856.The protein had one signal peptide between site 1 and 26,with 44 α-helix,8 β-sheet and 43 coils.The phylogenetic tree showed that the evolution distance of crucian carp ghrelin gene was the most homogeneous to goldfish ghrelin gene.