Codon optimality controls differential mRNA translation during amino acid starvation

Area of Science:

• Molecular Biology
• Genetics
• Cellular Biology

Background:

• Codon usage bias is typically associated with efficient translation of highly expressed genes using optimal codons.
• Emerging evidence indicates non-optimal codons may play regulatory roles in translation dynamics.

Purpose of the Study:

• To investigate the role of non-optimal codons in selective mRNA translation during amino acid starvation in mammalian cells.
• To understand how codon composition influences the translation of different gene groups under stress conditions.

Main Methods:

• Analysis of codon composition in genes encoding ribosomal proteins versus those in the ubiquitin-proteasome system.
• Experimental validation of the selective tRNA charging model under starvation.
• Use of luciferase reporters to assess the impact of codon optimality on mRNA translation.

Main Results:

• Non-optimal codons are enriched in genes of the ubiquitin-proteasome system, which are less sensitive to amino acid deprivation.
• tRNA isoacceptors for rare codons remain associated with translating ribosomes during starvation.
• Codon optimality significantly affects differential mRNA translation in response to amino acid starvation.

Conclusions:

• Non-optimal codons are critical for selective mRNA translation and cellular adaptation to amino acid starvation.
• Codon usage bias plays a significant physiological role in stress response mechanisms.