The AtPPT1 gene encoding 4-hydroxybenzoate polyprenyl diphosphate transferase in ubiquinone biosynthesis is required for embryo development in Arabidopsis thaliana
The AtPPT1 gene encoding 4-hydroxybenzoate polyprenyl diphosphate transferase in ubiquinone biosynthesis is required for embryo development in Arabidopsis thaliana
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DOI：
10.1007/s11103-004-1298-4
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发表时间：
2004-07-01
影响因子：
5.1
通讯作者：
Yamane, H
中科院分区：
文献类型：
--
作者：
Okada, K;Ohara, K;Yamane, H
4-羟基苯甲酸聚异戊二烯基二磷酸转移酶（4 HPT）是泛醌（UQ）生物合成中将异戊二烯基侧链转移到苯醌框架中的关键酶。根据拟南芥基因组序列信息，采用RT-PCR技术克隆了拟南芥AtPPT 1基因的cDNA，并对其功能进行了研究。AtPPT 1基因的异源表达能够恢复4 HPT活性缺陷的酵母突变体的呼吸能力和UQ合成。从表达AtPPT 1基因的酵母突变体制备的线粒体级分显示出以香叶基二磷酸（GPP）作为异戊烯基底物的4 HPT酶活性。这表明AtPPT 1基因编码活性4 HPT，其对异戊二烯供体具有广泛的底物特异性。AtPPT 1 mRNA主要在花簇中表达，与AtPPT 1信号肽融合的绿色荧光蛋白（GFP）转位到线粒体中。T-DNA插入突变破坏了拟南芥AtPPT 1基因，导致合子胚发生早期胚胎发育停滞。这些结果表明，参与线粒体UQ生物合成的AtPPT 1基因在拟南芥胚胎发育中起着至关重要的作用。
4-Hydroxybenzoate polyprenyl diphosphate transferase (4HPT) is the key enzyme that transfers the prenyl side chain to the benzoquione frame in ubiquinone (UQ) biosynthesis. The Arabidopsis AtPPT1 cDNA encoding 4HPT was cloned by reverse transcription-polymerase chain reaction (RT-PCR) based on the information of the Arabidopsis genomic sequence, and the function of the gene was determined. Heterologous expression of the AtPPT1 gene enabled restoration of the respiratory ability and UQ synthesis in a yeast mutant that was defective in 4HPT activity. The mitochondrial fraction that was prepared from the yeast mutant, which expressed the AtPPT1 gene, exhibited 4HPT enzymatic activity with geranyl diphosphate (GPP) as the prenyl substrate. This indicated that the AtPPT1 gene encodes active 4HPT with a broad substrate specificity in terms of the prenyl donor. The AtPPT1 mRNA was predominantly expressed in the flower cluster, and the green fluorescent protein (GFP) fused with the signal peptide of AtPPT1 was translocated into the mitochondria. T-DNA insertion mutation that disrupts the AtPPT1 gene in Arabidopsis resulted in the arrest of embryo development at an early stage of zygotic embryogenesis. These results demonstrate that the AtPPT1 gene involved in the biosynthesis of mitochondrial UQ plays an essential role in embryo development in Arabidopsis.