Highly efficient 5′ capping of mitochondrial RNA with NAD+ and NADH by yeast and human mitochondrial RNA polymerase
Highly efficient 5′ capping of mitochondrial RNA with NAD+ and NADH by yeast and human mitochondrial RNA polymerase
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DOI：
10.7554/elife.42179
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发表时间：
2018-12-12
期刊：
影响因子：
7.7
通讯作者：
Nickels, Bryce E.
中科院分区：
文献类型：
--
作者：
Bird, Jeremy G.;Basu, Urmimala;Nickels, Bryce E.
细菌和真核生物核糖核酸聚合酶(RNAPs)是利用NAD(+)和NADH作为非规范的转录起始核苷酸，将代谢效应因子烟酰胺腺嘌呤二核苷酸(NAD(+))和NADH(+)与氧化和还原形式的代谢效应物(NAD(+)和NADH)结合在一起的RNA。在这里，我们证明了线粒体RNAP(MtRNAP)用NAD(+)和NADH覆盖RNA，并且比核RNAP更有效。直接定量NAD(+)和NADH封顶的RNA表明，在体内有非常高的封顶水平：酵母线粒体转录本的NAD(+)和NADH封顶水平高达60%，人类线粒体转录本的NAD(+)封顶水平高达15%。封端效率由转录起始点及其上游的启动子序列决定，在酵母和人类细胞中，由细胞内NAD(+)和NADH水平决定。我们的发现表明，mtRNAP既是细胞代谢的传感器，也是执行器，连接细胞代谢和线粒体转录输出，感知NAD(+)和NADH水平，并相应地调节转录输出。
Bacterial and eukaryotic nuclear RNA polymerases (RNAPs) cap RNA with the oxidized and reduced forms of the metabolic effector nicotinamide adenine dinucleotide, NAD(+) and NADH, using NAD(+) and NADH as non-canonical initiating nucleotides for transcription initiation. Here, we show that mitochondrial RNAPs (mtRNAPs) cap RNA with NAD(+) and NADH, and do so more efficiently than nuclear RNAPs. Direct quantitation of NAD(+)- and NADH-capped RNA demonstrates remarkably high levels of capping in vivo: up to similar to 60% NAD(+) and NADH capping of yeast mitochondrial transcripts, and up to similar to 15% NAD(+) capping of human mitochondrial transcripts. The capping efficiency is determined by promoter sequence at, and upstream of, the transcription start site and, in yeast and human cells, by intracellular NAD(+) and NADH levels. Our findings indicate mtRNAPs serve as both sensors and actuators in coupling cellular metabolism to mitochondrial transcriptional outputs, sensing NAD(+) and NADH levels and adjusting transcriptional outputs accordingly.