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DNA polymerase gamma, the mitochondrial replicase.
1Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824-1319, USA. lskaguni@msu.edu
Annual Review of Biochemistry
|June 11, 2004
Summary
Mitochondrial DNA polymerase gamma (pol gamma) replicates and repairs mitochondrial DNA. Its high fidelity prevents mutations and toxicity, crucial for mitochondrial health.
Area of Science:
- Mitochondrial Biology
- Molecular Genetics
- Biochemistry
Background:
- Animal mitochondria possess a single DNA polymerase, pol gamma, essential for DNA replication.
- Historically, DNA repair and recombination were considered absent in mitochondria, but recent evidence shows their presence.
Observation:
- Pol gamma functions as a heterodimeric holoenzyme with a catalytic core and accessory subunit.
- This holoenzyme demonstrates high fidelity in nucleotide selection and proofreading via its 3' to 5' exonuclease activity.
Findings:
- Pol gamma is responsible for DNA synthesis in mitochondrial replication, repair, and recombination.
- Proofreading failures of pol gamma during nucleotide analog incorporation cause mitochondrial toxicity, linked to antiviral therapies.
- Errors in pol gamma's replication process lead to mitochondrial mutagenesis and dysfunction.
Implications:
- Understanding pol gamma's function is critical for developing safe antiviral therapies.
- Pol gamma's role in maintaining mitochondrial DNA integrity is vital for preventing disease.
- Further research into pol gamma and associated replication fork proteins can illuminate mitochondrial dysfunction.