五种鲤科鱼类生长激素cDNA的克隆和序列分析

通过RT-PCR方法,以草鱼、鳙鱼、鲫鱼、鲤鱼、齐口裂腹鱼等5种鲤科重要经济鱼类的垂体总RNA为模板扩增出其生长激素(fish growth hormone,fGH)的完整ORF序列,并克隆到pMD18-T载体上,命名为pMD-1(草鱼)、pMD-2(鳙鱼)、pMD-3(鲫鱼)、pMD-4(鲤鱼)、pMD-5(齐口裂腹鱼)。测序结果显示,ORF序列其长度均为633 bp。序列分析表明,所有ORF序列均以ATG为起始密码,以TAG为终止密码,编码210个氨基酸残基,推导的生长激素前体由22个氨基酸的信号肽和188个氨基酸的成熟肽组成。同源性分析表明,草鱼、鳙鱼、鲤鱼、鲫鱼和齐口裂腹鱼的fGH同源性在93.3%~99.5%之间。

Molecular Cloning and Sequence Analysis of the cDNAs Encoding Growth Hormone of Five Kinds of Fishes of Carp Family

The 5 cDNAs encoding fish growth hormone(fGH) genes were amplified by RT-PCR from five important economic fishes,Ctenopharyngodon idella,Hypophthalmichthys molitrix,Carassius aureate,Cyprinus carpio and Schizothorax prenanti based on the total RNA obtained from pituitary gland,and were cloned to pMD18-T vector,and designated pMD-1,pMD-2,pMD-3,pMD-4 and pMD-5,respectively.It is the first time to clone GH cDNAs of S.prenant in China.The lengths of the open reading frame(ORF) of all the cDNAs are 633 bp.Sequence analysis showed that each complete ORF(cDNA) of the above fishes includes the same start codon of ATG and the same end codon of TAG,and encodes a protein of about 210 amino acids,which is composed of signal sequence of 22 amino acids and mature peptide sequence of 188 amino acids.Bioinformatics analysis showed that the identity of fGH is located at 93.3%-99.5%.