RNA capping by mitochondrial and multi-subunit RNA polymerases

Recently, it was found that bacterial and eukaryotic transcripts are capped with cellular cofactors installed by their respective RNA polymerases (RNAPs) during transcription initiation. We now show that mitochondrial RNAP efficiently caps transcripts with ADP - containing cofactors. However, a functional role of universal RNAP - catalysed capping is not yet clear.