# Mechanisms of Eukaryotic Translation with a Focus on Induced Nonsense Suppression

> **NIH NIH R01** · UNIVERSITY OF PENNSYLVANIA · 2024 · $334,750

## Abstract

SUMMARY
We propose to determine i) the specific effects on eukaryotic translation of posttranscriptional modifications (PTMs) of
mRNA and tRNA and ii) how readthrough of premature termination codons (PTCs) is modulated by downstream sequence
context and stimulated by translation readthrough inducing drugs (TRIDs). In so doing we will contribute to the
development of new therapeutic approaches for treatment of diseases which are linked to PTMs and PTCs. Our approach
is to apply a reconstituted in vitro system, denoted PURE‐LITE, to elucidate mechanisms of elongation and termination
using a combination of ensemble and single molecule approaches. Such studies can aid in interpreting the results of
related cellular and clinical studies and suggest new directions to pursue. Our Specific Aims are: 1. Determine the effects
of mRNA and tRNA posttranscriptional modifications on elongation and termination. m6A, pseudoU (,inosine (I) and
m5C are among the most common PTMs of eukaryotic mRNA. There currently are no direct measurements of how these
PTMs affect cognate elongation, misreading, readthrough and termination. We will determine which modifications have
the most pronounced effects on these processes and identify which steps during elongation and termination are
responsible for these effects, which are the most likely to be involved in altering translational functions in cells. We will
prepare mRNAs containing modifications in sense or nonsense codons, pair these modified codons with cognate and near‐
cognate tRNAs for the three elongation processes, and compare the rates and stoichiometries of elongation with those
obtained with the corresponding unmodified mRNAs and tRNAs. tRNAs will be selected to examine how different
modifications of nucleotides 34 and 37 of the anticodon loop affect assay results. Similar studies for termination will
compare modified and unmodified mRNAs. 2. Determine the effects on readthrough of UGA codons of downstream
sequence context and TRID termination inhibitors. There is strong evidence that UGA PTCs are the most susceptible to
readthrough and that sequences immediately downstream from a UGA PTC influence readthrough efficiency. Our results
have demonstrated that ataluren, the only TRID currently approved for treating patients with a PTC disease, acts
exclusively by competitively inhibiting release factor complex (RFC). Ataluren shows variable results in stimulating
readthrough, as measured in cell‐based assays and clinical trials. We hypothesize that this variability may be a
consequence of how PTC downstream sequence affects RFC activity. We will test this hypothesis by determining how
closely ataluren inhibition of RFC as a function of downstream sequence correlates with ataluren stimulation of
readthrough activity. Such tests will be repeated with ataluren added in combination with agents which stimulate
readthrough by a mechanism orthogonal to that of ataluren, potentially leading to synergistic results. The most...

## Key facts

- **NIH application ID:** 10802736
- **Project number:** 2R01GM127374-05A1
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** BARRY S. COOPERMAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $334,750
- **Award type:** 2
- **Project period:** 2018-05-01 → 2028-05-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10802736

## Citation

> US National Institutes of Health, RePORTER application 10802736, Mechanisms of Eukaryotic Translation with a Focus on Induced Nonsense Suppression (2R01GM127374-05A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10802736. Licensed CC0.

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