Rice P1B-type heavy-metal ATPase, OsHMA9, is a metal efflux protein
Rice P1B-type heavy-metal ATPase, OsHMA9, is a metal efflux protein
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DOI：
10.1104/pp.107.102236
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发表时间：
2007-11-01
期刊：
影响因子：
7.4
通讯作者：
An, Gynheung
中科院分区：
文献类型：
--
作者：
Lee, Sichul;Kim, Yu-Young;An, Gynheung
P-1B型重金属ATP酶（HMAs）是跨膜转运金属的蛋白质，在金属稳态中起关键作用。尽管它们的重要性，很少有人知道他们在单子叶植物的功能。我们报道了水稻（Oryza sativa）OsHMA 9的特性，OsHMA 9是P（1B）-型ATP酶家族的成员。半定量逆转录-聚合酶链反应分析表明，OsHMA 9的表达诱导高浓度的铜（Cu），锌（Zn）和镉。我们还通过启动子：：β-葡萄糖醛酸酶分析确定，该基因主要在维管束和花药中表达. OsHMA 9：绿色荧光蛋白融合体定位于质膜。OsHMA 9的异源表达部分地挽救了大肠杆菌copA突变体的铜敏感性，该突变体在铜转运ATP酶中有缺陷。它不能挽救锌转运ATP酶缺陷的zntA突变体的锌敏感性。为了进一步阐明OsHMA 9的功能作用，我们从T-DNA插入群体中分离了两个独立的无效等位基因，oshma 9 - 1和oshma 9 -2。突变体植物表现出的表型增加的敏感性，高水平的铜，锌，铅。这些结果支持OsHMA 9在Cu、Zn和铅从细胞流出中的作用。本文首次报道了单子叶植物P-1B型金属外排转运蛋白的功能特性。
P-1B-type heavy-metal ATPases (HMAs) are transmembrane metal- transporting proteins that play a key role in metal homeostasis. Despite their importance, very little is known about their functions in monocot species. We report the characterization of rice (Oryza sativa) OsHMA9, a member of the P (1B)- type ATPase family. Semiquantitative reverse transcription- polymerase chain reaction analyses of seedlings showed that OsHMA9 expression was induced by a high concentration of copper (Cu), zinc (Zn), and cadmium. We also determined, through promoter:: beta- glucuronidase analysis, that the main expression was in the vascular bundles and anthers. The OsHMA9: green fluorescence protein fusion was localized to the plasma membrane. Heterologous expression of OsHMA9 partially rescued the Cu sensitivity of the Escherichia coli copA mutant, which is defective in Cu- transporting ATPases. It did not rescue the Zn sensitivity of the zntA mutant, which is defective in Zn- transporting ATPase. To further elucidate the functional roles of OsHMA9, we isolated two independent null alleles, oshma9- 1 and oshma9-2, from the T- DNA insertion population. Mutant plants exhibited the phenotype of increased sensitivity to elevated levels of Cu, Zn, and lead. These results support a role for OsHMA9 in Cu, Zn, and lead efflux from the cells. This article is the first report on the functional characterization of a P-1B- type metal efflux transporter in monocots.