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

Deletions of LSM1 and PBP1 from S. cerevisiae decrease growth rates (122,123). In contrast, we detected only minor decrease in the growth rate of the lsm1Δ strain and no difference in the growth rate of the pbp1Δ strain from the growth rate of their parental wild-type strain, K. lactis IFO1267 (Fig. 7A) . Disruption of any of the three genes tested enhanced production of the toxin encoded by the linear cytoplasmic plasmid pGKL1, and the production was most enhanced in the lsm1Δ strain. The increased toxin production by the slow-growing K. lactis The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/325316 doi: bioRxiv preprint corresponding AUG start codon. This transcriptome analysis allowed us to refine the description of the pGKL promoters and revealed new alternative promoters for the K1ORF4, K2ORF3 and K2ORF4 genes. We also provide evidence that K2ORF3 codes for the long sought mRNA cap guanine-N 7 methyltransferase and that capped pGKL transcripts contain The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/325316 doi: bioRxiv preprint Precise manipulation of pGKL plasmids in vivo revealed the indispensability of the K2Orf3p MTase active site for plasmid maintenance and an essential role of pGKL promoters in mRNA capping and non-template-based 5' polyadenylation.