Pseudouridinylation of mRNA coding sequences alters translation

Area of Science:

• Molecular Biology
• Biochemistry
• RNA Biology

Background:

• Chemical modifications of RNA regulate gene expression.
• Messenger RNA (mRNA) modifications, particularly in coding regions, are increasingly recognized for their functional importance.
• Pseudouridine (Ψ) is a prevalent mRNA modification impacting RNA structure and function.

Purpose of the Study:

• To investigate the impact of pseudouridine (Ψ) on protein synthesis.
• To elucidate the molecular mechanisms by which Ψ affects translation.
• To determine the consequences of Ψ incorporation on mRNA decoding and peptide production.

Main Methods:

• Utilized a reconstituted bacterial translation system.
• Employed human cell-based assays.
• Determined a crystal structure of the ribosome complexed with a Ψ-modified codon.

Main Results:

• Pseudouridine (Ψ) impedes amino acid addition and elongation factor (EF-Tu) GTPase activation during translation.
• A crystal structure revealed how Ψ in a codon affects tRNA binding in the ribosome's A site.
• Ψ promotes low-level synthesis of multiple peptides from a single mRNA and increases near-cognate tRNA binding.

Conclusions:

• Pseudouridine (Ψ) in mRNA coding regions modestly alters translation speed and mRNA decoding.
• Ribosome interaction with Ψ can lead to altered peptide synthesis outcomes.
• These findings highlight the role of mRNA modifications in regulating protein production.