Mitochondrial RNA capping: highly efficient 5’-RNA capping with NAD+ and NADH by yeast and human mitochondrial RNA polymerase

Bird, J. G.; Basu, U.; Kuster, D.; Ramachandran, A.; Grudzien-Nogalska, E.; Kiledjian, M.; Temiakov, D.; Patel, S. S.; Ebright, R. H.; Nickels, B. E.

doi:10.1101/381160

bioRxiv · 10.1101/381160

Mitochondrial RNA capping: highly efficient 5’-RNA capping with NAD+ and NADH by yeast and human mitochondrial RNA polymerase

Bird, J. G.·Basu, U.·Kuster, D.·Ramachandran, A.·Grudzien-Nogalska, E.·Kiledjian, M.·Temiakov, D.·Patel, S. S.·Ebright, R. H.·Nickels, B. E.

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Abstract

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 ~60% NAD+ and NADH capping of yeast mitochondrial transcripts, and up to ~10% 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 gene expression, sensing NAD+ and NADH levels and adjusting transcriptional outputs accordingly.

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Bird, J. G., Basu, U., Kuster, D., Ramachandran, A., Grudzien-Nogalska, E., Kiledjian, M., Temiakov, D., Patel, S. S., Ebright, R. H., Nickels, B. E.. 2018-07-31. Mitochondrial RNA capping: highly efficient 5’-RNA capping with NAD+ and NADH by yeast and human mitochondrial RNA polymerase. https://doi.org/10.1101/381160

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