荷那龙罗非鱼两种GHSR基因的克隆与序列分析

Molecular Clone and Sequence Analysis of GHSR Gene of Zanzibar Tilapia(Oreochromis hornorum)

用RT-PCR和RACE方法,从荷那龙罗非鱼(Oreochromis hornorum)垂体中克隆到生长激素促分泌素受体(GHSR)cDNA全序列。荷那龙罗非鱼GHSR基因具有GHSR-1a与GHSR-1b两个高度保守cDNA序列。GHSR-1a序列全长1 646 bp,包括225 bp的5′非编码区,266 bp的3′非编码区和1 155 bp的开放阅读框,编码384个氨基酸残基,具有7个跨膜结构域结构(transmembrane domains,TM);GHSR-1b序列全长1 877 bp,包括225 bp的5′非编码区,755 bp的3′非编码区和897 bp的开放阅读框,编码298个氨基酸残基,只具有前5个TM,在第6个TM的第4个氨基酸处开始缺失。将GHSR cDNA序列与基因组序列比较发现,这两种cDNA转录本来自同一个基因的不同变体。

Two cDNA transcripts,namely GHSR-1a and GHSR-1b,for growth hormone secretagogue receptor（GHSR） were identified from the zanzibar tilapia（Oreochromis hornorum） pituitary by RT-PCR and RACE method.The GHSR-1a,1 627 bp in length,consists of a 225-bp 5′-untranslated region,a 266-bp 3′-untranslated region and a 1 155-bp open reading frame（ORF） encoding 384 amino acids and including seven transmembrane domains（TM）.The GHSR-1b,1 877 bp in length,consists of a 225-bp 5′-untranslated region,a 755-bp 3′-untranslated region and a 897-bp ORF encoding 298 amino acids and including five TM.Comparison between cDNA and gene sequences of GHSR showed that the two transcripts were two alternative splicing forms of a single GHSR gene.