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Related Concept Videos

Translesion DNA Polymerases02:10

Translesion DNA Polymerases

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Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
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DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart,...
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Related Experiment Video

Updated: Jun 15, 2025

DNA Polymerase Activity Assay Using Near-infrared Fluorescent Labeled DNA Visualized by Acrylamide Gel Electrophoresis
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Small molecules restore mutant mitochondrial DNA polymerase activity.

Sebastian Valenzuela1, Xuefeng Zhu1, Bertil Macao1

  • 1Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden.

Nature
|April 9, 2025
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Summary
This summary is machine-generated.

Scientists discovered PZL-A, a novel small molecule that activates mitochondrial DNA (mtDNA) synthesis. This compound restores function to mutant DNA polymerase gamma (POLγ), offering hope for treating POLG disorders and mtDNA depletion diseases.

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Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • Mammalian mitochondrial DNA (mtDNA) replication relies on DNA polymerase gamma (POLγ), a complex with catalytic POLγA and accessory POLγB subunits.
  • Over 300 mutations in the POLG gene cause severe POLG disorders, leading to high morbidity and mortality with no current treatments.

Purpose of the Study:

  • To discover and characterize a novel small molecule capable of activating mtDNA synthesis.
  • To investigate the potential of this molecule to restore function to mutant POLγ variants and treat POLG-related diseases.

Main Methods:

  • Discovery and characterization of PZL-A, a small-molecule activator of mtDNA synthesis.
  • In vitro assays to assess PZL-A's effect on mutant POLγ activity.
  • Cellular studies using patient-derived cells to evaluate PZL-A's impact on mtDNA synthesis and cellular respiration.

Main Results:

  • PZL-A binds to an allosteric site on POLγ, unaffected by most disease-causing mutations.
  • The compound restored wild-type-like activity to mutant POLγ in vitro.
  • PZL-A activated mtDNA synthesis in cells from patients with lethal POLG disease, enhancing oxidative phosphorylation and cellular respiration.

Conclusions:

  • Small molecules can restore function to mutant DNA polymerases.
  • PZL-A represents a first-in-class therapeutic strategy for POLG disorders.
  • This approach holds promise for treating a range of severe conditions linked to mtDNA depletion.