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A nascent polypeptide domain that can regulate translation elongation.
Peng Fang1, Christina C Spevak, Cheng Wu
1Department of Environmental and Biomolecular Systems, OGI School of Science & Engineering, Oregon Health & Science University, Beaverton, OR 97006-8921, USA.
Summary
The fungal arginine attenuator peptide (AAP) regulates translation by stalling ribosomes when arginine is abundant. This peptide-sensing mechanism is conserved across fungal, plant, and animal systems, even within larger proteins.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The fungal arginine attenuator peptide (AAP) is an evolutionarily conserved sequence that halts ribosome activity during translation.
- AAP's function is linked to sensing high concentrations of the amino acid arginine.
Purpose of the Study:
- To investigate if the regulatory function of AAP is conserved in cell-free translation systems from fungi, plants, and animals.
- To determine if AAP retains its function when positioned internally or near the N-terminus of a polypeptide.
Main Methods:
- Pulse-chase analysis of radiolabeled polypeptides synthesized in cell-free systems.
- Toeprint analysis to map ribosome positions on transcripts in the fungal system.
Main Results:
- Wild-type AAP successfully stalled polypeptide synthesis in response to arginine across fungal, plant, and animal systems.
- AAP's regulatory function was observed regardless of its position (N-terminus or internal) within the polypeptide.
- Toeprint analyses confirmed that ribosome stalling occurred only after translating the AAP coding sequence.
Conclusions:
- The peptide-sensing capabilities of AAP are conserved in eukaryotic ribosomes (fungal, plant, and animal).
- Internal polypeptide domains can regulate eukaryotic translational elongation in response to small molecules.
- These findings establish a precedent for using nascent polypeptide domains to modulate gene expression via translational control.