Messenger RNAs transcribed from yeast linear cytoplasmic plasmids possess unconventional 5’ and 3’ UTRs and suggest a novel mechanism of translation

Václav Vopálenský; Michal Sýkora; Tomáš Mašek; Martin Pospíšek

The 5' RACE analysis of the pGKL transcripts revealed a unique and surprising composition of 5' ends. Eukaryotic mRNAs generally contain an m 7 G cap structure at their 5' ends, which is a prerequisite for their stability and efficient translation initiation (72) (73) (74) . Even though the pGKL plasmids encode their own putative capping enzyme (K2Orf3p), we found that few pGKL1/2 genes give rise to the frequently 5'-capped transcripts and that most of the transcripts contain a short leader of non-template adenosine nucleotides (1-20) at their 5' ends that could not have been continuously transcribed from the plasmids (Figs. 2E, 3A and C, 7B;