2'-O-methylation of the second transcribed nucleotide in eukaryotic RNA 5’ cap impacts protein production levels and susceptibility to DXO-mediated transcript degradation

ABSTRACT: Eukaryotic mRNA 5’ end is decorated with cap structure which plays multiple roles in the cell. Most importantly, protects transcript from exonucleolytic degradation and enables translation of encoded protein conducted by cap-dependent machinery. This is also a key feature in the process of recognizing RNA as self or non-self molecule by cellular innate immune system. Cap is composed of 7-methylguanosine linked by a 5′,5′-triphosphate chain to the first transcribed nucleotide, and is formed enzymatically during transcription. This m7GpppN structure, called cap0, can be further modified by CMTR1 methyltransferase to cap1 (m7GpppNm), which predominates in eukaryotic cells. Cap2, with additional 2′-O-methylation at the second transcribed nucleotide (m7GpppNmpNm) added by another methyltransferase CMTR2, also can be found at mRNA 5’ end. We present new tools allowing for in vitro synthesis of RNAs possessing cap2, i.e tetranucleotide cap analogues. Utilizing these for in vitro transcription reactions we obtained RNAs with 2′-O-methylation present at the second transcribed nucleotide. Due to that we investigated the role of cap2 in protein production from reporter mRNA protected with this structure in different conditions, normal or stress ones, or with CMTR1/2 down regulated level. We also assessed the affinity of eIF4E protein to differentially capped RNAs. Furthermore, we verified whether an additional 2′-O-methylation presence in capped RNA makes transcript more resistant to decapping enzyme action.

INSTRUMENT(S): Orbitrap Exploris 480

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

SUBMITTER: Dominik Cysewski  

LAB HEAD: Paweł Sikorski

PROVIDER: PXD028636 | Pride | 2022-09-08

REPOSITORIES: Pride