大海马垂体糖蛋白激素α亚基的cDNA克隆和序列分析  

MOLECULAR CLONING AND SEQUENCE ANALYSIS OF THE cDNA ENCODING PITUITARY GLYCOPROTEIN HORMONE α SUBUNIT OF SEAHORSE HIPPOCAMPUS KUDA BLEEKER

作　　者：张利红[1] 张为民[1] 成佳[1] 张扬[1] 吴金英[1] 

机构地区：[1]中山大学生命科学学院,广州510275

出　　处：《水生生物学报》2007年第1期53-58,共6页Acta Hydrobiologica Sinica

基　　金：国家863计划课题(2002AA624010);国家自然科学基金项目(No.30170130)资助

摘　　要：大海马(Hippocampus kudaBleeker)隶属鱼纲海龙目,是一种名贵的海产中药材,也是重要的海洋保护鱼类。我们通过快速扩增cDNA末端(rapid amplification of cDNA ends,RACE)的方法,首次从大海马的垂体总RNA中扩增出其垂体糖蛋白激素α亚基(pituitary glycoprotein hormoneαsubunit,PGHα)全长cDNA,其cDNA全长741bp(不包括polyA尾),5′和3′非编码区分别含有76和314bp,开放读码框为351bp,编码117aa的PGHα亚基前体(包括23aa的信号肽和94aa的成熟肽)。和其他脊椎动物一样,大海马PGHα亚基含有10个半胱氨酸残基,2个脯氨酸残基和2个N-糖基化位点。序列分析发现,大海马PGHα亚基的成熟肽与其他物种的同源性为50%—61.7%,其中与鲈形目和合鳃目的同源性最高(61.7%),而其信号肽与其他物种的同源性仅为8.7%—39.1%左右。这些结果表明大海马与已知的脊椎动物PGHα亚基同源性都比较低,是一种比较独特的鱼类。大海马PGHα亚基的全长cDNA克隆对海马垂体糖蛋白激素的结构和功能研究以及海马的养殖和保护有着重要的意义。In this study, we report, for the first time, the cloning of the cDNA for pituitary glycoprotein hormone a subunit （PGH a） from seahorse, Hippocampus kuda Bleeker, a species of Syngnathiformes. The full length PGH α cDNA was obtained using 5＇- and 3＇-rapid amplification of cDNA ends （RACE）. The full-length cDNA for the PGH a of H. kuda was 741bp in size excluding the poly （A） tail,with a 5＇ UTR of 76bp,a 3＇ UTR of 314bp,and an open reading frame of 351bp,which encodes a protein of 117 amino acids with a putative signal peptide of 23 amino acid residues and a mature peptide of 94 amino acids. All 10 cysteine residues,2 putative N-linked glycosylation sites, and two proline residues （P^41 and P^43） are conserved. Sequence analysis re vealed that the PGH α mature peptide of H. kuda shares 50 -61.7 % amino acid identity with other vertebrates, and the highest identity（61.7 % ） with tilapia, a member of Pereiformes, and with rice-field eel, a member of Synbranchiformes, respectively. The PGH α signal peptide of H. kuda shares 8.7%-39.1% amino acid identity with mammalian, avian, amphibian, and other fish. These results indicate that the PGH α of seahorse H. kuda shares relatively low homology with those of other vertebrates, and even other fish examined,suggesting seahorse H. kuda is a special fish and worth further study.

关 键 词：大海马 糖蛋白激素a亚基 CDNA克隆 

分 类 号：Q343[生物学—遗传学]