黄瓜质膜型Na~+/H~+逆向转运蛋白基因(SOS1)的克隆与序列分析

采用RACE(rapid-amplification of cDNA ends)方法从黄瓜Cucumis sativusL.中克隆出质膜Na+/H+逆向转运蛋白基因的cDNA(CsSOS1),该cDNA全长3 638bp,其中开放阅读框为3 435bp,编码1 145个氨基酸。氨基酸同源性分析表明,CsSOS1氨基酸序列与水稻OsSOS1和拟南芥AtSOS1的氨基酸序列同源性较高,分别为64%和58%,而与液泡型的Na+/H+逆向转运蛋白氨基酸序列亲缘关系较远。蛋白质跨膜结构分析表明CsSOS1包含11个完全跨膜片段。激光共聚焦显微镜显示CsSOS1基因的编码区与YFP基因融合后,定位在细胞膜上。酵母功能互补试验结果显示CsSOS1参与Na+与H+的转运,表明该基因转化酵母后可以补充酵母SOS1的缺失。

Cloning and Sequence Analysis of a Plasma Membrane Na+/H+ Antiporter Gene from Cucumis sativus L.

A plasma membrane Na+ /H+ antiporter gene(CsSOS1) has been separated from Cucumis sativus L.by RACE(rapid-amplification of cDNA ends).The full-length cDNA of CsSOS1 is 3 638 bp with an open reading frame(ORF) of 3 435 bp encoding a protein of 1 145 amino acids.Multiple sequence alignment analysis of amino acids shown that the identities in amino acids to plasma membrane Na+/H+ antiporters gene of AtSOS1(64%) and OsSOS1(58%) respectively.Transmembrane structure prediction showed CsSOS1 possessed 11 transmembrane domains.Phylogenetic analysis indicates that CsSOS1 is more related to plasma membrane type Na+/H+ antiporter,compared with vacuolar type Na+/H+ antiporter,to which it is less related.Analysis of the subcellular localization revealed that this protein located to the plasma membrane.Heterologous expression of CsSOS1 in ATX3 yeast Na+/H+ antiporter mutants showed functional complementation.