1-methylpseudouridine

Description

N1-Methylpseudouridine is a modified nucleoside used for enhancing mRNA translation. Incorporation of N1-Methylpseudouridine into mRNA turns off the immune/eIF2α phosphorylation-dependent inhibition of translation, and increases ribosome pausing and density on the mRNA, thus dramatically facilitating the translation process. N1-Methylpseudouridine outperforms several other modified nucleosides (e.g. 5-Methylcytidine) and corresponding combinations in terms of translation capacity.

Definition

ChEBI: 1-methylpseudouridine is a methylpseudouridine in which the methyl group is located at position N-1 on the uracil ring.

What are the applications of Application

1-Methylpseudouridine is a substitute for uridine in modified mRNA. This substitution has shown to increase transfection by reducing immuogenicity. The 1-methylpseudouridine substituted mRNA increases protein expression due to low immune stimulation as it evades detection by the edosomal Toll-like receptor (TLR3).

Biochem/physiol Actions

N1-methylpseudouridine (m1Ψ), the modification used in the current mRNA SARS-CoV-2 vaccines, was found to possess superior characteristics to Ψ; m1Ψ elicited less immunogenicity and increased protein production by more than an order of magnitude relative to Ψ m1Ψ preserves the fidelity of tRNA selection by the ribosome. Kim et al. explored the effect of m1Ψ and Ψ on decoding using various in vitro systems. They found that m1Ψ slightly decreases the rate of peptide-bond formation. It also suppresses near-stop codon recognition by release factors and m1Ψ-modified SARS-CoV-2 spike protein mRNA is translated faithfully by eukaryotic ribosomes. Unlike Ψ, m1Ψ does not stabilize mismatches during RNA-duplex formation. Ψ, but not m1Ψ, increases errors by reverse transcriptases[3].

References

1. Svitkin YV, Cheng YM, Chakraborty T, et al. N1-methyl-pseudouridine in mRNA enhances translation through eIF2α-dependent and independent mechanisms by increasing ribosome density. Nucleic Acids Research, 2017, 45(10): 6023-6036.
2. Andries O, Mc Cafferty S, De Smedt SC, et al N(1)-methylpseudouridine-incorporated mRNA outperforms pseudouridine-incorporated mRNA by providing enhanced protein expression and reduced immunogenicity in mammalian cell lines and mice. Journal of Controlled Release, 2015, 217: 337-344.
3. Kyusik Q Kim. “N1-methylpseudouridine found within COVID-19 mRNA vaccines produces faithful protein products.” Cell reports 40 9 (2022): 111300.