Identification and Characterization of AtSTP14, a Novel Galactose Transporter from Arabidopsis
Identification and Characterization of AtSTP14, a Novel Galactose Transporter from Arabidopsis
复制标题
DOI：
10.1093/pcp/pcq100
复制
发表时间：
2010-09-01
影响因子：
4.9
通讯作者：
Buettner, Michael
中科院分区：
文献类型：
--
作者：
Poschet, Gernot;Hannich, Barbara;Buettner, Michael
ATSTP14是一种新的拟南芥糖转运蛋白，并在分子和生理水平上进行了表征。逆转录分析和记者植物在种子胚乳和子叶以及绿叶中表现出较高的ATSTP14表达水平。因此，与先前表征的单糖转运蛋白不同，ATSTP14在源和下沉组织中均表达，代表了女配子体中的第一个单糖转运蛋白。酵母中的异源表达表明，ATSTP14不转运葡萄糖或果糖，而是第一个针对半乳糖的植物转运蛋白。有趣的是，ATSTP14的表达受诱导细胞壁降解的因素（例如延长的黑暗时期或糖水平的变化）的调节，即ATSTP14被24H黑暗诱导3倍，并用2葡萄糖和2个蔗糖抑制3倍。确定了两种独立的ATSTP14突变线，但是在正常条件下未观察到对种子发育或生长期间其他差异的影响。讨论了ATSTP14在不同发育过程中细胞壁衍生的半乳糖回收中的推定作用。
AtSTP14, a new Arabidopsis sugar transporter, was identified and characterized on the molecular and physiological level. Reverse transcriptasePCR analyses and reporter plants demonstrate high AtSTP14 expression levels in the seed endosperm and in cotyledons, as well as in green leaves. Thus, unlike previously characterized monosaccharide transporters, AtSTP14 is expressed in both source and sink tissues and represents the first monosaccharide transporter in the female gametophyte. Heterologous expression in yeast revealed that AtSTP14 does not transport glucose or fructose, but is the first plant transporter specific for galactose. Interestingly, AtSTP14 expression is regulated by factors which also induce cell wall degradation such as extended dark periods or changes in the sugar level, i.e. AtSTP14 is induced 3-fold by 24h darkness and repressed 3-fold by 2 glucose and 2 sucrose. Two independent Atstp14 mutant lines were identified, but no effect on seed development or other differences during growth under normal conditions could be observed. A putative role for AtSTP14 in the recycling of cell wall-derived galactose during different developmental processes is discussed.