scholarly journals A novel interaction between DNA ligase III and DNA polymerase γ plays an essential role in mitochondrial DNA stability

2007 ◽  
Vol 402 (1) ◽  
pp. 175-186 ◽  
Author(s):  
Ananya De ◽  
Colin Campbell
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Mitochondrial Protein ◽  
Dna Ligase ◽  
Zinc Finger Domain ◽  
Wild Type ◽  
Mitochondrial Dna Copy Number ◽  
Dna Polymerase Γ ◽  
Dna Ligase Iii

The data in the present study show that DNA polymerase γ and DNA ligase III interact in mitochondrial protein extracts from cultured HT1080 cells. An interaction was also observed between the two recombinant proteins in vitro. Expression of catalytically inert versions of DNA ligase III that bind DNA polymerase γ was associated with reduced mitochondrial DNA copy number and integrity. In contrast, overexpression of wild-type DNA ligase III had no effect on mitochondrial DNA copy number or integrity. Experiments revealed that wild-type DNA ligase III facilitates the interaction of DNA polymerase γ with a nicked DNA substrate in vitro, and that the zinc finger domain of DNA ligase III is required for this activity. Mitochondrial protein extracts prepared from cells overexpressing a DNA ligase III protein that lacked the zinc finger domain had reduced base excision repair activity compared with extracts from cells overexpressing the wild-type protein. These data support the interpretation that the interaction of DNA ligase III and DNA polymerase γ is required for proper maintenance of the mammalian mitochondrial genome.

scholarly journals Sensitive Assay for Mitochondrial DNA Polymerase γ

1999 ◽  
Vol 45 (10) ◽  
pp. 1725-1733 ◽  
Author(s):  
Robert K Naviaux ◽  
David Markusic ◽  
Bruce A Barshop ◽  
William L Nyhan ◽  
Richard H Haas
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Dynamic Range ◽  
Mitochondrial Protein ◽  
Reaction Products ◽  
Clinical Assay ◽  
Mitochondrial Dna Depletion ◽  
Mitochondrial Dna Polymerase ◽  
Muscle Biopsies ◽  
Dna Polymerase Γ

Abstract Background: The mitochondrial DNA polymerase γ is the principal polymerase required for mitochondrial DNA replication. Primary or secondary deficiencies in the activity of DNA polymerase γ may lead to mitochondrial DNA depletion. We describe a sensitive and robust clinical assay for this enzyme. Methods: The assay was performed on mitochondria isolated from skeletal muscle biopsies. High-molecular weight polynucleotide reaction products were captured on ion-exchange paper, examined qualitatively by autoradiography, and quantified by scintillation counting. Results: Kinetic analysis of DNA polymerase γ by this method showed a Km for dTTP of 1.43 μmol/L and a Ki for azidothymidine triphosphate of 0.861 μmol/L. The assay was linear from 0.1 to 2 μg of mitochondrial protein. The detection limit was 30 units (30 fmol dTMP incorporated in 30 min). The linear dynamic range was three orders of magnitude; 30–30 000 units. Imprecision (CV) was 6.4% within day and 12% between days. Application of this assay to a mixed population of 38 patients referred for evaluation of mitochondrial disease revealed a distribution with a range of 0–2506 U/μg, reflecting extensive biologic variation among patients with neuromuscular disease. Conclusion: This assay provides a useful adjunct to current laboratory methods for the evaluation of patients with suspected mitochondrial DNA depletion syndromes.

scholarly journals Deleterious mitochondrial DNA point mutations are overrepresented in Drosophila expressing a proofreading-defective DNA polymerase γ

PLoS Genetics ◽  
2018 ◽  
Vol 14 (11) ◽  
pp. e1007805 ◽  
Author(s):  
Colby L. Samstag ◽  
Jake G. Hoekstra ◽  
Chiu-Hui Huang ◽  
Mark J. Chaisson ◽  
Richard J. Youle ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Point Mutations ◽  
Dna Polymerase Γ

scholarly journals Mitochondrial DNA polymerase-γ and human disease

2006 ◽  
Vol 15 (suppl_2) ◽  
pp. R244-R252 ◽  
Author(s):  
Gavin Hudson ◽  
Patrick F. Chinnery
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Human Disease ◽  
Mitochondrial Dna Polymerase ◽  
Dna Polymerase Γ

Genomic Structure of Murine Mitochondrial DNA Polymerase-γ

2000 ◽  
Vol 19 (10) ◽  
pp. 601-605 ◽  
Author(s):  
Justin L. Mott ◽  
Grace Denniger ◽  
Steve J. Zullo ◽  
H. Peter Zassenhaus
Keyword(s):  
Mitochondrial Dna ◽  
Dna Polymerase ◽  
Genomic Structure ◽  
Mitochondrial Dna Polymerase ◽  
Dna Polymerase Γ

Effect of temperature on transition and transversion mutagenesis: characterization of wild type and a mutator T4 DNA polymerase mutant

1984 ◽  
Vol 26 (3) ◽  
pp. 386-389 ◽  
Author(s):  
Linda J. Reha-Krantz ◽  
Sükran Parmaksizoglu
Keyword(s):  
Dna Polymerase ◽  
Low Temperatures ◽  
Bacteriophage T4 ◽  
Effect Of Temperature ◽  
In Vitro Mutagenesis ◽  
Wild Type ◽  
Mutational Site

The effect of temperature on genetically well-defined mutational pathways was examined in the bacteriophage T4. The mutational site was a T4 rII ochre mutant which could revert to rII+ via a transversion or to the amber convertant via a transition. Temperature did not strongly affect any of the pathways examined in a wild-type background; however, increased temperature reduced the mutational activity of a mutator DNA polymerase mutant. Possible models to explain the role of temperature in mutagenesis are discussed as well as the significance of low temperatures for in vitro mutagenesis reactions.Key words: bacteriophage T4, mutator, transition, transversion, temperature effects.

scholarly journals Molecular cloning and expression of human cDNAs encoding a novel DNA ligase IV and DNA ligase III, an enzyme active in DNA repair and recombination.

1995 ◽  
Vol 15 (6) ◽  
pp. 3206-3216 ◽  
Author(s):  
Y F Wei ◽  
P Robins ◽  
K Carter ◽  
K Caldecott ◽  
D J Pappin ◽  
...  
Keyword(s):  
Dna Repair ◽  
Cdna Clone ◽  
Dna Ligase ◽  
Dna Ligases ◽  
Dna Ligase Iv ◽  
Ligase Iv ◽  
Dna Ligase I ◽  
Cloned Cdna ◽  
Dna Ligase Iii

Three distinct DNA ligases, I to III, have been found previously in mammalian cells, but a cloned cDNA has been identified only for DNA ligase I, an essential enzyme active in DNA replication. A short peptide sequence conserved close to the C terminus of all known eukaryotic DNA ligases was used to search for additional homologous sequences in human cDNA libraries. Two different incomplete cDNA clones that showed partial homology to the conserved peptide were identified. Full-length cDNAs were obtained and expressed by in vitro transcription and translation. The 103-kDa product of one cDNA clone formed a characteristic complex with the XRCC1 DNA repair protein and was identical with the previously described DNA ligase III. DNA ligase III appears closely related to the smaller DNA ligase II. The 96-kDa in vitro translation product of the second cDNA clone was also shown to be an ATP-dependent DNA ligase. A fourth DNA ligase (DNA ligase IV) has been purified from human cells and shown to be identical to the 96-kDa DNA ligase by unique agreement between mass spectrometry data on tryptic peptides from the purified enzyme and the predicted open reading frame of the cloned cDNA. The amino acid sequences of DNA ligases III and IV share a related active-site motif and several short regions of homology with DNA ligase I, other DNA ligases, and RNA capping enzymes. DNA ligases III and IV are encoded by distinct genes located on human chromosomes 17q11.2-12 and 13q33-34, respectively.

Sign in / Sign up

Export Citation Format

Share Document