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Interactions between peptidyl tRNA hydrolase homologs and the ribosomal release factor Mrf1 in S. pombe mitochondria

Laurent Dujeancourt1, Ricarda Richter, Zofia M Chrzanowska-Lightowlers

  • 1Centre de Génétique Moléculaire, UPR3404, FRC3115, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France.

Mitochondrion
|July 30, 2013
PubMed

Insights

In yeast, a protein called Pth4 compensates for the loss of mitochondrial translation termination factor Mrf1. Pth4

Area of Science:

  • Mitochondrial biology
  • Molecular genetics
  • Protein synthesis

Background:

  • Mitochondrial translation is essential for producing subunits of respiratory complexes.
  • In Schizosaccharomyces pombe, the absence of Mrf1 (mitochondrial stop codon recognition factor) is tolerated, implying alternative termination mechanisms.
  • S. pombe possesses four predicted peptidyl-tRNA hydrolases, with Pth3 and Pth4 containing a conserved GGQ motif characteristic of class I release factors.

Purpose of the Study:

  • To investigate the role of peptidyl-tRNA hydrolases, specifically Pth4, in mitochondrial translation termination in S. pombe.
  • To determine if Pth4 can functionally replace Mrf1 in yeast mitochondrial translation termination.

Main Methods:

  • Genetic analysis of S. pombe strains with deletions or high expression of Mrf1 and Pth4.
  • Biochemical assays to determine the localization and function of Pth4 within the mitochondrial ribosome.

Main Results:

  • High expression of Pth4 rescues the viability of S. pombe lacking Mrf1.
  • Deletion of Pth4 worsens the phenotype of Mrf1-deficient strains.
  • Pth4 was identified as a component of the mitochondrial ribosome.

Conclusions:

  • Pth4 plays a significant role in mitochondrial translation termination in S. pombe, capable of compensating for Mrf1.
  • Pth4's association with the mitochondrial ribosome suggests a direct role in ribosome recycling and preventing translation errors.
Keywords:
Fission yeastMitochondriaMitochondrial ribosome taggingPeptidyl tRNA hydrolaseRelease factorTranslation

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