biostudies-literatureKrawczyk PSEuropean Research Council984-992https://www.ebi.ac.uk/biostudies/studies/S-EPMC12095053biostudies-literatureUnknown641(8064)Despite the widespread use of mRNA vaccines against COVID-19, little is known about the metabolism of therapeutic RNAs. Here we use nanopore sequencing^1-3 to analyse individual therapeutic mRNA molecules, focusing on their poly(A) tails. We show that the Moderna mRNA-1273 vaccine⁴ has a poly(A) tail of around 100 nucleotides, followed by an mΨCmΨAG sequence. In cell lines, mRNA-1273 undergoes rapid degradation initiated by mΨCmΨAG removal, followed by CCR4-NOT-mediated deadenylation. However, in medically relevant preclinical models, particularly in macrophages, mRNA-1273 poly(A) tails are extended to up to 200 nucleotides by the TENT5A poly(A) polymerase^5-7, which is induced by the vaccine. Re-adenylation, which stabilizes target mRNAs, is consistently obsNatureRe-adenylation by TENT5A enhances efficacy of SARS-CoV-2 mRNA vaccines.PMC12095053101097317Affek KJelen SBrouze AJemielity JTudek ANowis DGolab JWesolowska AOrzel WAntczak WTurowski PKasztelan KGuminska NSpiewla TMroczek SMazur MTarkowski BMatylla-Kulinska KSroka MKusio-Kobialka MOwczarek EPGewartowska OKrawczyk PSDziembowski AKowalska JfalseRe-adenylation by TENT5A enhances efficacy of SARS-CoV-2 mRNA vaccines.Despite the widespread use of mRNA vaccines against COVID-19, little is known about the metabolism of therapeutic RNAs. Here we use nanopore sequencing^1-3 to analyse individual therapeutic mRNA molecules, focusing on their poly(A) tails. We show that the Moderna mRNA-1273 vaccine⁴ has a poly(A) tail of around 100 nucleotides, followed by an mΨCmΨAG sequence. In cell lines, mRNA-1273 undergoes rapid degradation initiated by mΨCmΨAG removal, followed by CCR4-NOT-mediated deadenylation. However, in medically relevant preclinical models, particularly in macrophages, mRNA-1273 poly(A) tails are extended to up to 200 nucleotides by the TENT5A poly(A) polymerase^5-7, which is induced by the vaccine. Re-adenylation, which stabilizes target mRNAs, is consistently obs2025-01-01T00:00:00Z2025 May2026-06-02T20:45:12.516Z2026-04-20T03:10:50.438ZS-EPMC120950534024060310.1038/s41586-025-08842-1