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Rapid Isolation of the Mitoribosome from HEK Cells
Published on: October 4, 2018
Translation termination in human mitochondrial ribosomes
Ricarda Richter1, Aleksandra Pajak, Sven Dennerlein
1Mitochondrial Research Group, Institute for Ageing and Health, Newcastle University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
Biochemical Society Transactions
|December 2, 2010
Summary
Human mitochondria may not use AGA and AGG as stop codons. Recent data suggest a -1 frameshift mechanism allows termination using only standard UAA and UAG stop codons, simplifying mitochondrial genetic code.
Area of Science:
- Cell Biology
- Genetics
- Molecular Biology
Background:
- Mitochondria possess their own genome (mtDNA) crucial for oxidative phosphorylation.
- Human mtDNA exhibits unusual codon usage, including UGA to tryptophan recoding.
- AGA and AGG codons are proposed to function as stop signals in human mtDNA.
Purpose of the Study:
- To investigate the apparent recoding of AGA and AGG codons in human mitochondria.
- To elucidate the molecular mechanism behind codon reassignment in mitochondrial translation.
- To determine if human mitochondria truly utilize AGA and AGG as termination signals.
Main Methods:
- Review of recent data on mammalian mitochondrial translation.
- Analysis of codon usage and tRNA availability in human mtDNA.
- Investigation of potential frameshift mechanisms in mitochondrial gene expression.
Main Results:
- Mammalian mitochondria can employ a -1 frameshift mechanism.
- This frameshift allows termination of all 13 polypeptides using only UAA and UAG stop codons.
- The necessity of AGA and AGG as stop codons may be reconsidered.
Conclusions:
- Human mitochondria might not require AGA and AGG as distinct stop codons.
- A -1 frameshift mechanism offers an alternative explanation for polypeptide termination.
- This finding simplifies the understanding of the mitochondrial genetic code.
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