Functional characterization and expression analysis of a glutathione transporter, BjGT1, from Brassica juncea:: evidence for regulation by heavy metal exposure
Functional characterization and expression analysis of a glutathione transporter, BjGT1, from Brassica juncea:: evidence for regulation by heavy metal exposure
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DOI：
10.1046/j.1365-3040.2003.01088.x
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发表时间：
2003-10-01
影响因子：
7.3
通讯作者：
Delrot, S
中科院分区：
文献类型：
--
作者：
Bogs, J;Bourbouloux, A;Delrot, S
谷氨酸及其衍生物在植物对重金属的耐受性中起着重要作用。从芥菜型油菜中克隆了谷胱甘肽转运蛋白BjGT 1（AJ 561120），并对其功能进行了研究。BjGT 1全长cDNA与酿酒酵母的高亲和力谷胱甘肽转运蛋白HGT 1同源，与A. thaliana（At4g16370）。当在S. BjGT 1在以谷胱甘肽为唯一硫源的培养基上补充突变株，并介导[H-3]GSH的摄取。针对C-末端序列的肽特异性抗血清的免疫印迹分析显示，BjGT 1在叶组织中表达较高，在茎组织中表达相对较低，而BjGT 1蛋白在根组织中检测不到。在B暴露6 d期间分析BjGT 1 mRNA和蛋白的量。25 μ M Cd（NO3）（2）.镉对茎和叶中BjGT 1的mRNA表达有强烈的诱导作用。出乎意料的是，BjGT 1蛋白在叶片中的量表现出显着的减少，最低后96小时的镉暴露，随后部分恢复。镉对BjGT 1的强烈调节表明了谷胱甘肽转运蛋白在重金属暴露过程中的作用。
Glutathione and its derivatives play an important role in the tolerance of plants against heavy metals. A glutathione transporter, BjGT1 (AJ561120), was cloned and functionally characterized from Brassica juncea, a plant which may be used for phytoremediation. The full-length BjGT1 cDNA showed homology with the high affinity glutathione transporter HGT1 from Saccharomyces cerevisiae and shares 92% identity with a putative glutathione transporter from A. thaliana (At4g16370). When expressed in the S. cerevisiae hgt1Delta strain, BjGT1 complemented the mutant on medium with glutathione as the only sulphur source and mediated the uptake of [H-3]GSH. Immunoblot analysis with a peptide-specific antiserum directed against a C-terminal sequence revealed high BjGT1 expression in leaf tissue and relatively low expression in stem tissue, whereas BjGT1 protein was not detectable in root tissue. The amounts of BjGT1 mRNA and protein were analysed during a 6 d exposure of B. juncea to 25 muM Cd(NO3)(2). BjGT1 mRNA was strongly induced by cadmium in stems and leaves. Unexpectedly, the amount of BjGT1 protein in leaves showed a pronounced decrease with a minimum after 96 h of Cd exposure, followed by partial recovery. The strong regulation of BjGT1 by cadmium suggests a role of this glutathione transporter during heavy metal exposure.