Properties and physiological functions of UDP-sugar pyrophosphorylase in Arabidopsis
Properties and physiological functions of UDP-sugar pyrophosphorylase in Arabidopsis
复制标题
DOI：
10.1271/bbb.60605
复制
发表时间：
2007-03-01
影响因子：
1.6
通讯作者：
Tsumuraya, Yoichi
中科院分区：
文献类型：
--
作者：
Kotake, Toshihisa;Hojo, Sachiko;Tsumuraya, Yoichi
在回收途径中，UDP-糖焦磷酸化酶催化各种单糖-1-磷酸转化为相应的UDP-糖。利用基因组数据库，我们克隆了拟南芥UDP-糖焦磷酸酶的一个可能的基因。虽然AtUSP在叶片和花粉的维管组织中有相对较强的表达，但AtUSP在拟南芥的大多数细胞类型中都有表达，这表明AtUSP在核苷酸糖代谢中具有看家功能。在大肠杆菌中表达的重组AtUSP对单糖1-磷酸表现出广泛的特异性，可形成UDP-葡萄糖、-半乳糖、-葡萄糖醛酸、-木糖和-L-阿拉伯糖等多种UDP-糖。插入T-DNA导致的AtUSP基因功能丧失突变完全消除了男性的生育能力。这些结果表明，AtUSP在抢救途径中作为一种UDP-糖焦磷酸化酶发挥作用，并且AtUSP催化的1-磷酸单糖产生UDP-糖是拟南芥花粉发育所必需的。
UDP-sugar pyrophosphorylase catalyzes the conversion of various monosaccharide 1-phosphates to the respective UDP-sugars in the salvage pathway. Using the genomic database, we cloned a putative gene for UDP-sugar pyrophosphorylase from Arabidopsis. Although relatively stronger expression was detected in the vascular tissue of leaves and the pollen, AtUSP is expressed in most cell types of Arabidopsis, indicating a housekeeping function in nucleotide sugar metabolism. Recombinant AtUSP expressed in Escherichia coli exhibited broad specificity toward monosaccharide 1-phosphates, resulting in the formation of various UDP-sugars such as UDP-glucose, -galactose, -glucuronic acid, -xylose and -L-arabinose. A loss-of-function mutation in the AtUSP gene caused by T-DNA insertion completely abolished male fertility. These results indicate that AtUSP functions as a UDP-sugar pyrophosphorylase in the salvage pathway, and that the generation of UDP-sugars from monosaccharide 1-phosphates catalyzed by AtUSP is essential for pollen development in Arabidopsis.