Localization of NAD-isocitrate dehydrogenase and glutamate dehydrogenase in rice roots: Candidates for providing carbon skeletons to NADH-glutamate synthase
Localization of NAD-isocitrate dehydrogenase and glutamate dehydrogenase in rice roots: Candidates for providing carbon skeletons to NADH-glutamate synthase
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DOI：
10.1093/pcp/pci188
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发表时间：
2005-10-01
影响因子：
4.9
通讯作者：
Yamaya, T
中科院分区：
文献类型：
--
作者：
Abiko, T;Obara, M;Yamaya, T
在水稻根部，提供 NH4+ 离子后，NADH 依赖性谷氨酸合酶 (NADH-GOGAT) 的 mRNA 和蛋白质会发生短暂且细胞类型特异性的积累。为了更好地了解该反应中 2-酮戊二酸的起源，我们重点研究了水稻根部线粒体 NAD 依赖性异柠檬酸脱氢酶 (IDH) 和谷氨酸脱氢酶 (GDH)。分离了编码单个催化 (OsIDHa) 和两个调节 (OsIDHc;1, OsIDHc;2) IDH 亚基和三个 GDH 蛋白 (OsGDH1-3) 的 6 个水稻 cDNA。除 OsGDH3 外，这些基因均在根中表达。实时PCR分析表明，在提供不同形式的无机氮后，OsIDHa和OsIDHc;1转录本，而不是OsGDH1和OsGDH2转录本，以与NADH-GOGAT mRNA类似的方式沿着冠根积累。此外，免疫定位研究揭示了根表面的两个细胞层（即表皮和外皮）中 IDHa 蛋白的 NH4+ 诱导，NADH-GOGAT 也在那里积累。讨论了 NADH-GOGAT、IDH 和 GDH 之间可能的关系。
In rice roots, transient and cell-type-specific accumulation of both mRNA and protein for NADH-dependent glutamate synthase (NADH-GOGAT) occurs after the supply of NH4+ ions. In order to better understand the origin of 2-oxoglutarate for this reaction, we focused on mitochondrial NAD-dependent isocitrate dehydrogenase (IDH) and glutamate dehydrogenase (GDH) in rice roots. Six rice cDNAs encoding a single catalytic (OsIDHa) and two regulatory (OsIDHc;1, OsIDHc;2) IDH subunits and three GDH proteins (OsGDH1-3) were isolated. These genes, except OsGDH3, were expressed in the roots. Real-time PCR analysis showed that OsIDHa and OsIDHc;1 transcripts, but not OsGDH1 and OsGDH2 transcripts, accumulated in a similar manner to NADH-GOGAT mRNA along the crown roots after the supply of different forms of inorganic nitrogen. Furthermore, immunolocalization studies revealed the NH4+ induction of IDHa protein in two cell layers of the root surface, i.e. epidermis and exodermis, where NADH-GOGAT also accumulated. The possible relationship between NADH-GOGAT, IDH and GDH is discussed.