麝香百合液泡膜水孔蛋白基因LlTIP2的克隆及生物信息学分析

Cloning and Bioinformatics Analysis of a Tonoplast Aquaporin Gene LlTIP2 in Lilium longiflorum

水孔蛋白是位于质膜和液泡膜等生物膜上主要负责水分跨膜运输的通道蛋白,属于膜主要内在蛋白(major intrinsic proteins,MIP)超家族。采用RT-PCR和RACE法从麝香百合(Lilium longiflorum)叶片克隆得到1个液泡膜内在蛋白(tonoplast intrinsic proteins,TIPs)基因的全长cDNA序列,命名为L1TIP2(GenBank登录号:JN085950)。该基因cDNA全长986 bp,包括208 bp的3'-非翻译区,744 bp开放阅读框以及34 bp的5'-非翻译区,共编码247个氨基酸。由L1TIP2推导的氨基酸序列具有2个高度保守的水孔蛋白NPA(Asn-Pro-Ala)基序以及MIP的特征序列SGGHVNPAVTFG。同源性分析表明,LlTIP2氨基酸序列与陆地棉(Gossypium hirsutum)、大麦(Hordeum vulgare)、黑麦草(Lolium perenne)和小麦(Triticum aestivum)等植物TIP2的同源性分别达77%、74%、73%和72%。系统进化树分析表明LlTIP2属于液泡膜水孔蛋白TIP2亚类新成员。

Aquaporins, belong to major intrinsic proteins （MIPs） superfamily, are channel proteins of biological membranes including plasma membrane and tonoplast, which highly facilitate the transportation of water across these membranes. A tonoplast intrinsic proteins （TIPs） gene （LITIP2, GenBank accession number： JN085950） was isolated from Lilium longiflorum leaves by RT-PCR and RACE. The full cDNA sequence of LIT1P2 was 986 bp, containing 208 bp 3＂ -UTR, 34 bp 5＂ -UTR, and 744 bp open reading frame, which encoded 247 amino acids, proposed as defining the specificity of aquaporins. Two highly conserved NPA （Asn-Pro-Ala） motifs of aquaporins and the MIP family signature sequence SGGHVNPAVTFG can be found in the deduced protein. Homology of amino acids sequences between LITIP2 and TIP2s from Gossypium hirsutum, Hordeum vulgare, Lolium perenne, and Triticum aestivum was 77%, 74%, 73% and 72% respectively. Phylogenetic analysis indicated that L1TIP2 was a new member of TIP2 subfamily.