The long-term objective of the proposed work is the elucidation of the mechanism of DNA replication in animal mitochondria, and its relationship to mitochondrial mutagenesis and human disease. A combined approach of current methods in biochemistry, structural biology and molecular genetics will be pursued to study the mechanism, structure and physiology of the mitochondrial replisome, with a focus on the replicative DNA helicase and the mitochondrial single-stranded DNA-binding protein. In combination with the extensive studies by us and others on the key replicative enzyme in mitochondria, DNA polymerase 3, we expand the scope of prior research to study the assembly and function of proteins at the mitochondrial DNA replication fork, and to probe the modes of mitochondrial DNA replication in vivo and in vitro. Mitochondria are the energy-producing organelle in animals and mitochondrial function impacts nearly every aspect of cellular function. Thus, mitochondria play a major role in human health and likewise, mitochondrial dysfunction is intricately associated with human disease. Mitochondrial dysfunction is implicated in a wide range of neurological diseases, in metabolic diseases, in muscular dystrophies and nephropathies, and in a broad spectrum of named disorders. Defects in mitochondrial biogenesis lead to mitochondrial DNA mutation, depletion and deletion syndromes that result in loss of mitochondrial and subsequent cellular function. The prevalence of mitochondrial genetic disease and recent recognition of the mitochondrial toxicity of antiviral and antimicrobial drugs the critical need for an in-depth understanding of the structure and functions of the mitochondrial DNA replication apparatus.

Public Health Relevance

Narrative: A common feature in diverse chronic, age-related diseases is a breakdown or disturbance in the cell's ability to produce energy. Central to the cellular energy production is the mitochondrion, an organelle that plays a crucial role in multiple metabolic processes, and whose dysfunction is linked directly to many pathologies, including those most represented in an aging population. Therefore, a clear understanding of mitochondrial biogenesis and energy production and how these processes are deregulated in common disease states, is essential to treating them effectively (and economically).

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
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Molecular Genetics A Study Section (MGA)
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Barski, Oleg
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Michigan State University
Schools of Arts and Sciences
East Lansing
United States
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Rosado-Ruiz, Fernando A; So, Minyoung; Kaguni, Laurie S (2016) Purification and Comparative Assay of the Human Mitochondrial Replicative DNA Helicase. Methods Mol Biol 1351:185-98
Gajewski, John P; Arnold, Jamie J; Salminen, Tiina S et al. (2016) Expression and Purification of Mitochondrial RNA Polymerase and Transcription Factor A from Drosophila melanogaster. Methods Mol Biol 1351:199-210
Ciesielski, G L; Oliveira, M T; Kaguni, L S (2016) Animal Mitochondrial DNA Replication. Enzymes 39:255-92
Kaguni, Laurie S; Oliveira, Marcos Túlio; Tamanoi, Fuyuhiko (2016) Preface. Enzymes 39:xi
Ciesielski, Grzegorz L; Hytönen, Vesa P; Kaguni, Laurie S (2016) Biolayer Interferometry: A Novel Method to Elucidate Protein-Protein and Protein-DNA Interactions in the Mitochondrial DNA Replisome. Methods Mol Biol 1351:223-31
Kaguni, Laurie S; Oliveira, Marcos T (2016) Structure, function and evolution of the animal mitochondrial replicative DNA helicase. Crit Rev Biochem Mol Biol 51:53-64
Ciesielski, Grzegorz L; Rosado-Ruiz, Fernando A; Kaguni, Laurie S (2016) Purification and Comparative Assay of Human Mitochondrial Single-Stranded DNA-Binding Protein. Methods Mol Biol 1351:211-22
Ciesielski, Grzegorz L; Bermek, Oya; Rosado-Ruiz, Fernando A et al. (2015) Mitochondrial Single-stranded DNA-binding Proteins Stimulate the Activity of DNA Polymerase γ by Organization of the Template DNA. J Biol Chem 290:28697-707
Farnum, Gregory A; Nurminen, Anssi; Kaguni, Laurie S (2014) Mapping 136 pathogenic mutations into functional modules in human DNA polymerase γ establishes predictive genotype-phenotype correlations for the complete spectrum of POLG syndromes. Biochim Biophys Acta 1837:1113-21
Stiban, Johnny; Farnum, Gregory A; Hovde, Stacy L et al. (2014) The N-terminal domain of the Drosophila mitochondrial replicative DNA helicase contains an iron-sulfur cluster and binds DNA. J Biol Chem 289:24032-42

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