The Adaptation Mechanism to Copper Deficiency via MicroRNA in Arabidopsis
The Adaptation Mechanism to Copper Deficiency via MicroRNA in Arabidopsis
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DOI：
10.1007/978-1-4020-6709-9_292
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Hiroaki Yamasaki;Salah E. Abdel‐Ghany;C. Cohu;Y. Kobayashi;M. Pilon;T. Shikanai
中科院分区：
文献类型：
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作者：
Hiroaki Yamasaki;Salah E. Abdel‐Ghany;C. Cohu;Y. Kobayashi;M. Pilon;T. Shikanai
铜是所有生物体必需的微量营养素。然而，过量的铜是有毒的，因为游离形式的铜会产生自由基。因此，细胞中的铜水平必须受到精确调节。在高等植物中，主要的铜蛋白是定位于叶绿体类囊体腔的质体蓝蛋白，以及定位于细胞质和叶绿体基质中的铜/锌超氧化物歧化酶。在铜限制条件下，铜/锌超氧化物歧化酶的表达下调，其功能由叶绿体中的铁超氧化物歧化酶补偿。在这里，我们提出了几条证据，表明 microRNA (miR398) 通过在铜有限时指导铜/锌超氧化物歧化酶 mRNA 的降解来参与拟南芥的这种调节。这种通过 miR398 的调节是针对铜浓度低于 0.5 μM 的变化而发生的，表明 miR398 参与了对铜限制的反应。另一方面，另一种主要的铜蛋白，质体蓝蛋白，其对于高等植物的光合作用电子流至关重要，不受miR398的调节。在低铜条件下，有限的铜优先被转运至质体蓝素。我们得出结论，miR398是高等植物铜稳态的关键因素。
Copper is an essential micronutrient for all living organisms. However, excess copper is toxic because of a production of free radicals via the free form of copper. Therefore, copper levels must be precisely regulated in a cell. In higher plants, major copper proteins are plastocyanin localized to the thylakoid lumen of chloroplasts, and copper/zinc superoxide dismutase localized to the cytoplasm and in the chloroplast stroma. Under copper-limited conditions, expression of copper/zinc superoxide dismutase is down-regulated and its function is compensated by iron superoxide dismutase in chloroplasts. Here, we present several lines of evidence indicating that microRNA,miR398, is involved in this regulation inArabidopsis thaliana, by directing degradation of copper/zinc superoxide dismutase mRNAs when copper is limited. This regulation viamiR398takes place in response to changes in copper concentration of less than 0.5 μM, indicating thatmiR398is involved in a response to copper limitation. On the other hand, another major copper protein, plastocyanin which essential for photosynthetic electron flow in higher plants was not regulated viamiR398. In low copper conditions, limited copper is preferentially transported to plastocyanin. We conclude thatmiR398is a key factor in copper homeostasis in higher plants.