# Reading frame maintenance by the ribosome during stalling

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2021 · $315,000

## Abstract

PROJECT SUMMARY/ABSTRACT
In all domains of life, decoding of the genetic information into peptides is accomplished by the ribosome,
which reads the messenger RNA (mRNA) three nucleotides at a time. Following careful selection of the
aminoacyl-tRNA that matches this triplet codon, the ribosome must precisely move to reading the next codon.
Precise translocation is not an easy task given the multiple coordinated movements of the mRNA, tRNA and
the ribosomal subunits that must occur. Failure to do so results in so-called frameshifting errors, which are
detrimental to proteostasis as they result in errant protein products that bear no resemblance to the encoded
ones. Notably, much of what we know about reading-frame maintenance comes from studies on programmed
or “intentional” frameshifting. These studies revealed that sequence and structural features of the mRNA and
its interaction with elements of the ribosome, translation factors and the tRNA contribute to these events.
Although many of these elements are unique to each mRNA, almost all frameshifting events rely on ribosome
stalling. Cellular response to stalls has been almost exclusively in the context of quality control and ribosome
rescue. In particular, stalls are recognized by ubiquitin ligases when they cause ribosome collisions. In
principle, colliding ribosomes can also provide structural impediments required for frameshifting; indeed, we
recently showed that collisions can lead to efficient +1 frameshifting, suggesting that cells must have evolved
factors to maintain reading frame during translation stalls. As ribosomes appear to stall frequently under
stress, these mechanisms are more than likely to become critical for cell survival and recovery. This proposal
is focused on one recently identified mechanism that involves the highly conserved multi-protein bridging
factor (Mbf1). Our preliminary studies suggest that the factor prevents collision-mediated +1 frameshifting.
This, together with a preliminary cyoEM structure of a Mbf1-bound ribosome, forms the basis of our major
hypothesis that Mbf1 recognizes collided ribosomes to prevent them from altering the reading frame of the
leading one. We will test this hypothesis through three aims. In the first one, we will assess how altering
ribosome density and mRNA-sequence and -structural features modulate the function of Mbf1 in an effort to
establish a relationship between ribosome collisions and frameshifting. In the second aim, using modified
ribosome-profiling approaches to assess frameshifting transcriptome-wide, we will dissect the role of Mbf1
in preventing frameshifting occurring at stochastic collisions as well as those experienced under stress. In
the third aim, the mechanism of Mbf1 recruitment to stalled ribosomes will be studied using a battery of
biochemical and biophysical approaches. We are most interested in investigating how the factor alters the
function and the structure of the translation machinery. Collectively, our int...

## Key facts

- **NIH application ID:** 10181827
- **Project number:** 1R01GM141474-01
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Hani Zaher
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $315,000
- **Award type:** 1
- **Project period:** 2021-04-27 → 2025-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10181827

## Citation

> US National Institutes of Health, RePORTER application 10181827, Reading frame maintenance by the ribosome during stalling (1R01GM141474-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10181827. Licensed CC0.

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