Characterization of the Arabidopsis clb6 mutant illustrates the importance of posttranscriptional regulation of the methyl-D-erythritol 4-phosphate pathway
Characterization of the Arabidopsis clb6 mutant illustrates the importance of posttranscriptional regulation of the methyl-D-erythritol 4-phosphate pathway
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DOI：
10.1105/tpc.104.028860
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发表时间：
2005-02-01
期刊：
影响因子：
11.6
通讯作者：
León, P
中科院分区：
文献类型：
--
作者：
Guevara-García, A;San Román, C;León, P
异戊烯基二磷酸和二甲基烯丙基二磷酸是类异戊二烯生物合成的两个基本单元，其生物合成在植物中通过两条独立的途径进行。甲羟戊酸途径在细胞质中起作用，甲基-D-β 4-磷酸（MEP）途径在质体中起作用。质体类异戊二烯在植物生长发育中起着重要作用。植物必须调节类异戊二烯的生物合成以满足特定组织和发育条件下的代谢需求。调节植物MEP途径的调节事件还没有很好地理解。在这篇文章中，我们证明了之前被证明是叶绿体发育所需的叶绿体生物发生6（CLB 6）基因编码1-羟基-2-甲基-丁烯基4-二磷酸还原酶，这是MEP途径的最后作用酶。在clb 6 -1突变体背景中的所有MEP途径基因转录本和蛋白质的表达水平的比较分析显示，转录后控制调节该中央途径中不同蛋白质的水平。转录后调节也被发现在幼苗发育过程中，在磷霉素抑制的途径。我们的研究结果表明，第一个酶的途径，1-脱氧-D-木酮糖5-磷酸合酶，反馈调节响应于中断的代谢物流通过MEP途径。
The biosynthesis of isopentenyl diphosphate and dimethylallyl diphosphate, the two building blocks for isoprenoid biosynthesis, occurs by two independent pathways in plants. The mevalonic pathway operates in the cytoplasm, and the methyl-D-erythritol 4-phosphate (MEP) pathway operates in plastids. Plastidic isoprenoids play essential roles in plant growth and development. Plants must regulate the biosynthesis of isoprenoids to fulfill metabolic requirements in specific tissues and developmental conditions. The regulatory events that modulate the plant MEP pathway are not well understood. In this article, we demonstrate that the CHLOROPLAST BIOGENESIS6 (CLB6) gene, previously shown to be required for chloroplast development, encodes 1-hydroxy-2-methyl-butenyl 4-diphosphate reductase, the last-acting enzyme of the MEP pathway. Comparative analysis of the expression levels of all MEP pathway gene transcripts and proteins in the clb6-1 mutant background revealed that posttranscriptional control modulates the levels of different proteins in this central pathway. Posttranscriptional regulation was also found during seedling development and during fosmidomycin inhibition of the pathway. Our results show that the first enzyme of the pathway, 1-deoxy-D-xylulose 5-phosphate synthase, is feedback regulated in response to the interruption of the flow of metabolites through the MEP pathway.