Oryza sativa polyamine oxidase 1 back-converts tetraamines, spermine and thermospermine, to spermidine
Oryza sativa polyamine oxidase 1 back-converts tetraamines, spermine and thermospermine, to spermidine
复制标题
DOI：
10.1007/s00299-013-1518-y
复制
发表时间：
2014-01-01
影响因子：
6.2
通讯作者：
Kusano, Tomonobu
中科院分区：
文献类型：
--
作者：
Liu, Taibo;Kim, Dong Wook;Kusano, Tomonobu
水稻多胺氧化酶1将精胺（或热精胺）反向转化为亚精胺。水稻（Oryza sativa）含有7个编码多胺氧化酶（PAOs）的基因，根据染色体数目和基因ID号分别命名为OsPAO 1 ~ OsPAO 7。我们以前表明，这些成员中的三个，OsPAO 3，OsPAO 4和OsPAO 5，大量表达，他们的产品定位于过氧化物酶体，并催化多胺的反向转化反应。在这里，我们重点关注OsPAO 1。OsPAO 1基因产物与拟南芥PAO 5和芥菜型油菜PAO基因产物具有高度的同源性。OsPAO 1在生理条件下表达量较低，但在精胺（Spm）和T-Spm处理下，OsPAO 1在水稻根中的表达量明显增加。与上述发现相一致，重组OsPAO 1在pH 6.0和pH 8.5下偏好T-Spm作为底物，并且在这两种情况下，将这些四胺逆转化为亚精胺，但不转化为腐胺。OsPAO 1定位于洋葱表皮细胞的细胞质中。水稻PAO中的OsPAO 1、OsPAO 3、OsPAO 4和OsPAO 5具有不同的亚细胞定位，催化PAs的反转化反应。在此基础上，讨论了多胺在水稻体内的代谢途径。
Key message Oryza sativa polyamine oxidase 1 back-converts spermine (or thermospermine) to spermidine. Considering the previous work, major path of polyamine catabolism in rice plant is suggestive to be back-conversion but not terminal catabolism.Rice (Oryza sativa) contains seven genes encoding polyamine oxidases (PAOs), termed OsPAO1 to OsPAO7, based on their chromosomal number and gene ID number. We previously showed that three of these members, OsPAO3, OsPAO4 and OsPAO5, are abundantly expressed, that their products localize to peroxisomes and that they catalyze the polyamine back-conversion reaction. Here, we have focused on OsPAO1. The OsPAO1 gene product shares a high level of identity with those of Arabidopsis PAO5 and Brassica juncea PAO. Expression of OsPAO1 appears to be quite low under physiological conditions, but is markedly induced in rice roots by spermine (Spm) or T-Spm treatment. Consistent with the above finding, the recombinant OsPAO1 prefers T-Spm as a substrate at pH 6.0 and Spm at pH 8.5 and, in both cases, back-converts these tetraamines to spermidine, but not to putrescine. OsPAO1 localizes to the cytoplasm of onion epidermal cells. Differing in subcellular localization, four out of seven rice PAOs, OsPAO1, OsPAO3, OsPAO4 and OsPAO5, catalyze back-conversion reactions of PAs. Based on the results, we discuss the catabolic path(s) of PAs in rice plant.