籼稻低亲和阳离子转运蛋白基因OsLCT2的克隆与生物信息学分析

Cloning and Bioinformatics Analysis of Low-affinity Cation Transporter Gene OsLCT2 in Indica Rice(Oryza sativa)

OsLCT1是目前在水稻中唯一鉴定出来的参与韧皮部镉离子运输的关键转运蛋白,与水稻籽粒镉积累密切相关。本研究根据Gene Bank已发表的小麦Ta LCT1基因序列信息设计引物,利用RT-PCR方法从籼稻93-11和华占中克隆了低亲和阳离子转运蛋白基因(LCT),并命名为OsLCT2。生物信息学分析结果表明,该基因定位在5号染色体上,全长2 699 bp,包含3个外显子和2个内含子,其CDS全长1 437 bp,编码478个氨基酸,包含2个PEST序列和11个跨膜结构域。OsLCT2蛋白二级结构预测显示,α-螺旋占57.11%、β-折叠占7.74%,无规则卷曲占35.15%。序列比对和系统进化树分析结果表明,OsLCT2与小麦的亲缘关系最近达65%,其次为高粱64%,而与水稻OsLCT1的同源性并不高,推测OsLCT2的功能可能与Ta LCT1相类似。

Current ly, OsLCT1 is the only identified key transport protein involved in phloem-mediated Cd transport in rice and closely related to the accumulation of cadmium （Cd） in rice （Oryza sativa L.） grains. In this study, based on the sequence information of wheat TaLCT1 published on GeneBank, the full length cDNA of L CT gene was obtained from Indica Rice （Oryza sativa L.） 93-11 and Huazhan by RT-PCR and named OsLCT2. Analysis of the OsLCT2 nucleotide sequence revealed that the full-length of the gene was located on Rice chromosome 5, composed of 3 exons and 2 introns was 2 699 bp in length, and its CDS consisted of 1 437 nucleotides encoding a 478 amino acid polypeptide. The bioinformatics analysis results showed that the protein contained two sequences of PEST and eleven transmembrane domains. The secondary structures of OsLCT2 were mainly e^-helix （57.11%）, B-sheet （7.74%） and random coil （35.15%）. With analysis of sequence alignment and phylogenetic tree, which indicated that OsLCT2 had the highest identity amino acid sequence with Triticum aestivum and Sorghum bicolor LCT 1 protein （respective 65% and 64%）, but lower with Oryza s ativa L.. It implied that function of OsLCT2 protein was similar to TaLCT1 protein.