Specialized yeast ribosomes: a customized tool for selective mRNA translation

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Ribosomes, the cellular machinery for protein synthesis, are increasingly recognized to exist as specialized sub-populations.
• These specialized ribosomes can preferentially translate specific messenger RNAs (mRNAs).
• Understanding these specialized ribosomes offers potential for novel therapeutic targets.

Purpose of the Study:

• To generate and characterize distinct populations of specialized ribosomes in eukaryotic cells.
• To investigate the preferential translation of specific mRNAs by these altered ribosomes.
• To identify specialized ribosomes that can enhance the synthesis of full-length proteins from mutated mRNAs.

Main Methods:

• Utilized a large collection of diploid yeast strains, each deficient in specific ribosomal protein (RP) genes.
• Employed comparative protein synthesis assays using heterologous mRNA reporters, including those with premature termination codons (PTCs).
• Examined the translation of laminin β3 (LAMB3) mRNA, focusing on a LAMB3-PTC mutant linked to Epidermolysis bullosa (EB).

Main Results:

• Demonstrated that distinct specialized ribosome populations preferentially translate different mRNA reporters.
• Identified specialized ribosomes that alter translation termination efficiency, enhancing wild-type protein synthesis from PTC-containing mRNAs.
• Discovered that specialized ribosomes with reduced RP L35B levels enhance full-length LAMB3 synthesis in cells with a LAMB3-PTC mutant.

Conclusions:

• Specialized ribosomes can be generated by altering ribosomal protein composition.
• Specific specialized ribosomes, such as those with reduced RP L35B, can selectively enhance the translation of disease-associated mRNA mutants.
• These findings highlight the potential of targeting specialized ribosomes for therapeutic interventions, particularly for genetic disorders like Epidermolysis bullosa.