Molecular cloning of a novel brain-type Na+-dependent inorganic phosphate cotransporter
Molecular cloning of a novel brain-type Na+-dependent inorganic phosphate cotransporter
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DOI：
10.1046/j.1471-4159.2000.0742622.x
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发表时间：
2000-06-01
影响因子：
4.7
通讯作者：
Takeda, J
中科院分区：
文献类型：
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作者：
Aihara, Y;Mashima, H;Takeda, J
我们分离出了编码一种蛋白质（称为DNPI）的人类cDNA，该蛋白质与人脑特异性Na+依赖性无机磷酸盐（Na+/P-i）协同转运蛋白（BNPI）显示出82%的氨基酸同一性和92%的相似性，BNPI专门定位于富含神经元的区域。DNPI mRNA在非洲爪蟾卵母细胞中的表达导致Na+依赖的P-i转运显著增加，表明DNPI是一种新的Na+/P-i共转运蛋白。北方印迹分析显示，DNPI mRNA主要在脑中表达，其中在髓质、黑质、丘脑底核和丘脑中观察到最高水平，所有这些都以低水平表达BNPI mRNA。相反，DNPI mRNA在小脑和海马中以低水平表达，其中BNPI mRNA以高水平表达。在胼胝体富含胶质细胞的区域没有DNPI mRNA的杂交信号。在其他检查区域，两种mRNA均中度或高度表达。这些结果表明，BNPI和DNPI，协调Na+-依赖性的P-i运输在大脑的神经元丰富的区域，可能形成一个新的类内的Na+/P-i协同转运蛋白家族。
We have isolated a human cDNA encoding a protein, designated DNPI, that shows 82% amino acid identity and 92% similarity to the human brain-specific Na+-dependent inorganic phosphate (Na+/P-i) cotransporter (BNPI), which is localized exclusively to neuron-rich regions. Expression of DNPI mRNA in Xenopus oocytes resulted in a significant increase in Na+-dependent P-i transport, indicating that DNPI is a novel Na+/P-i cotransporter. Northern blot analysis shows that DNPI mRNA is expressed predominantly in brain, where the highest levels are observed in medulla, substantia nigra, subthalamic nucleus, and thalamus, all of which express BNPI mRNA at low levels. In contrast, DNPI mRNA is expressed at low levels in cerebellum and hippocampus, where BNPI mRNA is expressed at high levels. No hybridizing signal for DNPI mRNA is observed in the glia-rich region of corpus callosum. In other regions examined, both mRNAs are moderately or highly expressed. These results indicate that BNPI and DNPI, which coordinate Na+-dependent P-i transport in the neuron-rich regions of the brain, may form a new class within the Na+/P-i cotransporter family.