Purification and characterization of an inducible mitochondrial DNA polymerase from Tetrahymena thermophila

1987 ◽  
Vol 908 (2) ◽  
pp. 150-157 ◽  
Author(s):  
Erik Østergaard ◽  
Peter Brams ◽  
Ole Westergaard ◽  
Ole F. Nielsen
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Tetrahymena Thermophila ◽  
Purification And Characterization ◽  
Mitochondrial Dna Polymerase

Partial purification and characterization of mitochondrial DNA polymerase from Plasmodium falciparum

2000 ◽  
Vol 49 (4) ◽  
pp. 279-288 ◽  
Author(s):  
Porntip Chavalitshewinkoon-Petmitr ◽  
Srisucha Chawprom ◽  
Lieve Naesens ◽  
Jan Balzarini ◽  
Prapon Wilairat
Keyword(s):  
Plasmodium Falciparum ◽  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Partial Purification ◽  
Purification And Characterization ◽  
Mitochondrial Dna Polymerase

scholarly journals Characterization of the mitochondrial DNA polymerase from Saccharomyces cerevisiae.

1994 ◽  
Vol 41 (1) ◽  
pp. 79-86 ◽  
Author(s):  
S Sen ◽  
S Mukhopadhyay ◽  
J Wetzel ◽  
T K Biswas
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Nuclear Dna ◽  
Dna Polymerase I ◽  
Specificity And Sensitivity ◽  
Protease Deficient ◽  
Polymerase I ◽  
Mitochondrial Dna Polymerase

The mitochondrial DNA (mtDNA) polymerase was isolated from a protease-deficient yeast strain (PY2), and purified about 3000 fold by a column chromatography on phosphocellulose, heparin-agarose, and single-stranded DNA cellulose. The purified polymerase was characterized with respect to optimal nucleotide concentrations, template-primer specificity and sensitivity to some inhibitors. These results were compared with the nuclear DNA polymerase I activity. Both polymerases showed similar requirement of deoxynucleotide concentrations (Km < 1 microM), and highest activity with poly(dA-dT) template. However, the mtDNA polymerase was more sensitive to ddTTP, EtBr and Mn2+ inhibition in comparison to the nuclear DNA polymerase I. The mtDNA polymerase did not need ATP as an energy source for in vitro DNA synthesis. This mtDNA polymerase preparation also showed 3'-->5' exonuclease activity.

scholarly journals In vivo and in vitro mechanistic characterization of a clinically relevant PolγA mutation

2020 ◽  
Author(s):  
Pedro Silva-Pinheiro ◽  
Carlos Pardo-Hernández ◽  
Aurelio Reyes ◽  
Lisa Tilokani ◽  
Anup Mishra ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Recessive Mutation ◽  
Accessory Subunit ◽  
Molecular Phenotypes ◽  
Protease Degradation ◽  
Mitochondrial Dna Polymerase

AbstractMutations in POLG, encoding POLγA, the catalytic subunit of the mitochondrial DNA polymerase, cause a spectrum of disorders characterized by mtDNA instability. However, the molecular pathogenesis of POLG-related diseases is poorly understood and efficient treatments are missing. Here, we generated a POLGA449T/A449T mouse model, which reproduces the most common human recessive mutation of POLG, encoding the A467T change, and dissected the mechanisms underlying pathogenicity. We show that the A449T mutation impairs DNA binding and mtDNA synthesis activities of POLγ in vivo and in vitro. Interestingly, the A467T mutation also strongly impairs interactions with POLγB, the homodimeric accessory subunit of holo-POLγ. This allows the free POLγA to become a substrate for LONP1 protease degradation, leading to dramatically reduced levels of POLγA, which in turn exacerbates the molecular phenotypes of PolgA449T/A449T mice. Importantly, we validated this mechanism for other mutations affecting the interaction between the two POLγ subunits. We suggest that LONP1 dependent degradation of POLγA can be exploited as a target for the development of future therapies.

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