Acclimation of Oxygenic Photosynthesis to Iron Starvation Is Controlled by the sRNA IsaR1
Acclimation of Oxygenic Photosynthesis to Iron Starvation Is Controlled by the sRNA IsaR1
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DOI：
10.1016/j.cub.2017.04.010
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发表时间：
2017-05-22
期刊：
影响因子：
9.2
通讯作者：
Hess, Wolfgang R.
中科院分区：
文献类型：
--
作者：
Georg, Jens;Kostova, Gergana;Hess, Wolfgang R.
含氧光合作用关键依赖于具有Fe（2+）或Fe/S络合物作为辅因子或辅基的蛋白质。在这里，我们表明，小调控RNA（sRNA）IsaR 1（铁应激激活RNA 1）在适应低铁条件中起着关键作用。IsaR 1调节子由超过15个直接靶点组成，包括参与光合电子传递、阴离子自由基解毒、柠檬酸循环和四吡咯生物发生的含Fe（2+）蛋白。IsaR 1是维持铁/硫簇生物合成蛋白在铁剥夺的生理水平是必不可少的。因此，IsaR 1在三个水平上影响光合机构对铁饥饿的适应：（1）直接，通过转录后抑制基因表达;（2）间接，通过抑制色素;和（3）Fe/S簇生物合成。IsaR 1的同源物在整个蓝藻门中广泛保守。我们得出结论，IsaR 1是一个非常重要的核糖核酸调节子。这些发现为理解光合生物体内铁稳态的调节提供了新的视角。
Oxygenic photosynthesis crucially depends on proteins that possess Fe (2+) or Fe/S complexes as co-factors or prosthetic groups. Here, we show that the small regulatory RNA (sRNA) IsaR1 (Iron-Stress-Activated RNA 1) plays a pivotal role in acclimation to low-iron conditions. The IsaR1 regulon consists of more than 15 direct targets, including Fe (2+)-containing proteins involved in photosynthetic electron transfer, detoxification of anion radicals, citrate cycle, and tetrapyrrole biogenesis. IsaR1 is essential for maintaining physiological levels of Fe/S cluster biogenesis proteins during iron deprivation. Consequently, IsaR1 affects the acclimation of the photosynthetic apparatus to iron starvation at three levels: (1) directly, via posttranscriptional repression of gene expression; (2) indirectly, via suppression of pigment; and (3) Fe/S cluster biosynthesis. Homologs of IsaR1 are widely conserved throughout the cyanobacterial phylum. We conclude that IsaR1 is a critically important riboregulator. These findings provide a new perspective for understanding the regulation of iron homeostasis in photosynthetic organisms.