PUBLICATION

Zebrafish lacking functional DNA polymerase gamma survive to juvenile stage, despite rapid and sustained mitochondrial DNA depletion, altered energetics and growth

Authors
Rahn, J.J., Bestman, J.E., Stackley, K.D., Chan, S.S.
ID
ZDB-PUB-151101-7
Date
2015
Source
Nucleic acids research   43(21): 10338-52 (Journal)
Registered Authors
Chan, Sherine, Rahn, Jennifer, Stackley, Krista
Keywords
none
MeSH Terms
  • Glycolysis
  • Animal Fins/physiology
  • Regeneration
  • DNA-Directed DNA Polymerase/chemistry
  • DNA-Directed DNA Polymerase/genetics*
  • DNA-Directed DNA Polymerase/metabolism
  • Zebrafish Proteins/chemistry
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/metabolism
  • Models, Animal
  • Zebrafish/genetics*
  • Zebrafish/growth & development
  • Mutation
  • Survival Analysis
  • Adenosine Triphosphate/metabolism
  • DNA, Mitochondrial/analysis*
  • Animals
  • Genetic Engineering
  • Oxygen Consumption
(all 19)
PubMed
26519465 Full text @ Nucleic Acids Res.
Abstract
DNA polymerase gamma (POLG) is essential for replication and repair of mitochondrial DNA (mtDNA). Mutations in POLG cause mtDNA instability and a diverse range of poorly understood human diseases. Here, we created a unique Polg animal model, by modifying polg within the critical and highly conserved polymerase domain in zebrafish. polg(+/-) offspring were indistinguishable from WT siblings in multiple phenotypic and biochemical measures. However, polg(-/-) mutants developed severe mtDNA depletion by one week post-fertilization (wpf), developed slowly and had regenerative defects, yet surprisingly survived up to 4 wpf. An in vivo mtDNA polymerase activity assay utilizing ethidium bromide (EtBr) to deplete mtDNA, showed that polg(+/-) and WT zebrafish fully recover mtDNA content two weeks post-EtBr removal. EtBr further reduced already low levels of mtDNA in polg(-/-) animals, but mtDNA content did not recover following release from EtBr. Despite significantly decreased respiration that corresponded with tissue-specific levels of mtDNA, polg(-/-) animals had WT levels of ATP and no increase in lactate. This zebrafish model of mitochondrial disease now provides unique opportunities for studying mtDNA instability from multiple angles, as polg(-/-) mutants can survive to juvenile stage, rather than lose viability in embryogenesis as seen in Polg mutant mice.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping
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Citation
Rahn, J.J., Bestman, J.E., Stackley, K.D., Chan, S.S. (2015) Zebrafish lacking functional DNA polymerase gamma survive to juvenile stage, despite rapid and sustained mitochondrial DNA depletion, altered energetics and growth. Nucleic acids research. 43(21):10338-52.