Delayed rRNA processing results in significant ribosome biogenesis and functional defects

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• The mof6-1 mutation in Saccharomyces cerevisiae affects programmed -1 ribosomal frameshifting and killer virus maintenance.
• Histone deacetylases play crucial roles in gene regulation and cellular processes.

Purpose of the Study:

• To identify the gene responsible for the mof6-1 mutation.
• To elucidate the role of histone deacetylase RPD3 in ribosomal frameshifting and virus maintenance.
• To investigate the mechanism by which RPD3 influences ribosome function.

Main Methods:

• Genetic analysis of the mof6-1 mutation in yeast.
• Complementation studies using the human homolog of RPD3.
• Analysis of rRNA processing and ribosome activity in wild-type and mutant strains.

Main Results:

• The mof6-1 mutation is an allele of the histone deacetylase gene RPD3.
• RPD3's deacetylase function is essential for normal ribosomal frameshifting and killer virus stability.
• Loss of RPD3 function leads to delayed rRNA processing, producing ribosomes with altered tRNA affinities and reduced peptidyltransferase activity.
• The human homolog of RPD3 can rescue these yeast defects.

Conclusions:

• RPD3-mediated histone deacetylation is critical for proper ribosome biogenesis and function.
• Defects in rRNA processing and ribosome activity underlie the increased frameshifting efficiencies observed in rpd3 mutants.
• These findings highlight a conserved role for histone deacetylases in regulating translation fidelity and viral stability.