革胡子鲶生长激素全长cDNA 的克隆与序列分析

通过RT-PCR和RACE-PCR的方法,克隆了革胡子鲶生长激素基因全长cDNA,其长度为973 bp,包含一个603 bp的开放阅读框架(Open reading frame,ORF),59 bp的5′非编码区和311 bp的3′非编码区(含PolyA 尾25 bp).将革胡子鲶GH cDNA的ORF、5′非编码区和3′非编码区的序列分别与同为鲶形目印度囊鳃鲶、巨鲶鱼、南方鲶和鲶的上述序列进行比对分析,结果表明:革胡子鲶与上述鱼类生长激素ORF的核苷酸与氨基酸序列同源性较高,平均值分别为91.2%和96.4%,ORF区核苷酸的碱基替代类型表现出T/C转换的偏向性,平均值为44.5%,同时表现出转换/颠换偏差,平均值为2.381.5′和3′非编码区序列同源性平均值分别为75.4%和77.0%,保守性低于编码区.

Cloning and Sequence Analysis of Full-length Growth Hormone cDNA from Clarias gariepinus

In this study,the GH full-length cDNA is cloned with the employment of RT-PCR and RACE-PCR techniques,which is 973 bp in length.The total length cDNA includes an open reading frame (ORF) of 603 bp,5′ UTR of 59 bp and 3′ UTR of 311 bp (Poly A of 25 bp included).Pairwise and multiple alignments of the sequences of ORF,5′ UTR,3′ UTR of Clarias gariepinus GH cDNA with those of Heteropneustes fossilis,Pangasianodon gigas,Silurus meridionalis and Silurus asotus are performed using DNAMAN 5.2.2 and MEGA 4.1 software.Sequence alignment analysis indicate that the average homologies are 91.2% and 96.4% separately for ORF nucleotide and amino acid sequence between Clarias gariepinus and the 4 species of Siluriforms catfish mentioned above.ORF nucleotide substitution patterns represent the bias of transition between T and C and the average value is 44.5%.Meanwhile,the base substitutions also show transition/transversion bias and the average ratio reaches 2.381.5′ UTR and 3′ UTR nucleotide sequence homology are 75.4% and 77.0%,respectively,which are lower conservative than that of ORF nucleotide sequence.