Related Experiment Video

Updated: Aug 14, 2026

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy
11:40

Preparation of the Mgm101 Recombination Protein by MBP-based Tagging Strategy

Published on: June 25, 2013

The yeast nuclear gene MRF1 encodes a mitochondrial peptide chain release factor and cures several mitochondrial RNA

H J Pel1, C Maat, M Rep

  • 1Department of Molecular Cell Biology, University of Amsterdam, The Netherlands.

Nucleic Acids Research
|December 11, 1992
PubMed

Insights

Researchers identified the MRF1 gene, crucial for mitochondrial protein synthesis in yeast. Its disruption causes mitochondrial genome instability and impaired translation, highlighting its essential role.

Area of Science:

  • Mitochondrial genetics
  • Molecular biology
  • Yeast genetics

Background:

  • Mitochondrial gene expression involves complex processing, including intron removal.
  • Polypeptide chain release factors are essential for terminating protein synthesis.
  • The specific factors involved in organellar protein termination were largely unknown.

Purpose of the Study:

  • To identify and characterize the gene encoding the mitochondrial polypeptide chain release factor in Saccharomyces cerevisiae.
  • To understand the function of this factor in mitochondrial protein synthesis and genome stability.

Main Methods:

  • Molecular cloning and sequencing of the MRF1 gene.
  • Genetic complementation of respiratory-deficient yeast mutants.
  • Gene disruption and analysis of resulting phenotypes.
  • Over-expression studies in a mitochondrial nonsense suppressor strain.

Main Results:

  • The MRF1 gene was cloned and sequenced, encoding a protein similar to prokaryotic release factor RF-1.
  • MRF1 gene disruption led to mitochondrial genome instability and impaired mitochondrial protein synthesis.
  • Mutants exhibited respiratory deficiency and reduced synthesis of mitochondrial translation products.
  • Over-expression of MRF1 affected nonsense suppression, implicating the 16S rRNA '530 region'.

Conclusions:

  • MRF1 is the first identified gene for an organellar polypeptide chain release factor.
  • MRF1 is essential for mitochondrial protein synthesis and maintaining mitochondrial genome stability in yeast.
  • The study provides insights into translational fidelity and the role of specific rRNA regions.

More Related Videos

Mitochondrial Transformation in Baker's Yeast to Study Translation and Respiratory Complex Assembly09:53

Mitochondrial Transformation in Baker's Yeast to Study Translation and Respiratory Complex Assembly

Published on: June 7, 2024

Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe08:07

Analysis of the Expression and Complexes Assembly of the Mitochondrial Respiratory Chain Proteins in the Fission Yeast Schizosaccharomyces pombe

Published on: May 2, 2025

Related Concept Videos

RNA Splicing01:32

RNA Splicing

Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
RNA Splicing01:32

RNA Splicing

Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...
Nonsense-mediated mRNA Decay02:27

Nonsense-mediated mRNA Decay

The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Riboswitches01:56

Riboswitches

Riboswitches are non-coding mRNA domains that regulate the transcription and translation of downstream genes without the help of proteins. Riboswitches bind directly to a metabolite and can form unique stem-loop or hairpin structures in response to the amount of the metabolite present. They have two distinct regions – a metabolite-binding aptamer and an expression platform.
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
Mitochondrial Protein Sorting01:39

Mitochondrial Protein Sorting

Mitochondria are double-membrane organelles of the eukaryotes involved in cellular metabolism, signaling, ATP synthesis, and programmed cell death.  Each of these processes requires specific proteins and enzymes that must be correctly sorted to the right mitochondrial subcompartment for the proper functioning of the organelle.
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...
Mitochondrial Precursor Proteins01:39

Mitochondrial Precursor Proteins

Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70  chaperones are targetted to TOM20-TOM22 receptor complexes.
Most of the mitochondrial precursors...