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Copeland W.C.,National Institute of Environmental Health and Safety
Critical Reviews in Biochemistry and Molecular Biology | Year: 2012

Mitochondrial DNA (mtDNA) is replicated by the DNA polymerase g in concert with accessory proteins such as the mtDNA helicase, single stranded DNA binding protein, topoisomerase, and initiating factors. Nucleotide precursors for mtDNA replication arise from the mitochondrial salvage pathway originating from transport of nucleosides, or alternatively from cytoplasmic reduction of ribonucleotides. Defects in mtDNA replication or nucleotide metabolism can cause mitochondrial genetic diseases due to mtDNA deletions, point mutations, or depletion which ultimately cause loss of oxidative phosphorylation. These genetic diseases include mtDNA depletion syndromes such as Alpers or early infantile hepatocerebral syndromes, and mtDNA deletion disorders, such as progressive external ophthalmoplegia (PEO), ataxia-neuropathy, or mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). This review focuses on our current knowledge of genetic defects of mtDNA replication (POLG, POLG2, C10orf2) and nucleotide metabolism (TYMP, TK2, DGOUK, and RRM2B) that cause instability of mtDNA and mitochondrial disease. © 2012 Informa Healthcare USA, Inc. Source


Copeland W.C.,National Institute of Environmental Health and Safety
Sub-cellular biochemistry | Year: 2010

Since mutations in mitochondrial DNA (mtDNA) have been shown to be a cause of many mitochondrial diseases as well as aging, it is important to understand the origin of these mutations and how replication proteins modulate this process. DNA polymerase gamma (pol gamma) is the polymerase that is responsible for replication and repair of mtDNA. Pol gamma has three main roles in mtDNA maintenance and mutagenesis. As the only known DNA polymerase in mitochondria, pol gamma is required for all replication and repair functions and is the main source of errors produced in human mtDNA. Pol gamma is also sensitive to a host of antiviral nucleoside analogs used to treat HIV-1 infections, which can cause an induced mitochondrial toxicity. Finally, the gene for pol gamma, POLG, is a genetic locus for several mitochondrial disease with over 150 genetic mutations currently identified. Source


Patent
INC Research, Emory University, National Institute of Environmental Health, Safety, Veterans Affairs Puget Sound Health Care System and University of Oregon | Date: 2012-10-19

The present invention relates to methods of treatment for Parkinson Disease (PD) in a person by identifying gene variants which may indicate a more favorable response to specific medicaments, thereby allowing for personalized or individualized treatment. The present invention relates to a method of screening for a genetic predisposition to PD in a person. The present invention is also directed to a method of testing a person for the presence of particular gene variants, wherein the presence of a gene variant indicates a higher predisposition to PD, and the absence of a gene variant indicates a lower predisposition to PD, compared to a control sample. The present invention further relates to methods and kits for treating, or inhibiting the development of, PD in a person. The present invention is also directed to a method of identifying the heritage of an individual based on the genetic profile of the individual.


Roberts S.A.,National Institute of Environmental Health and Safety | Gordenin D.A.,National Institute of Environmental Health and Safety
BioEssays | Year: 2014

The gain of a selective advantage in cancer as well as the establishment of complex traits during evolution require multiple genetic alterations, but how these mutations accumulate over time is currently unclear. There is increasing evidence that a mutator phenotype perpetuates the development of many human cancers. While in some cases the increased mutation rate is the result of a genetic disruption of DNA repair and replication or environmental exposures, other evidence suggests that endogenous DNA damage induced by AID/APOBEC cytidine deaminases can result in transient localized hypermutation generating simultaneous, closely spaced (i.e. "clustered") multiple mutations. Here, we discuss mechanisms that lead to mutation cluster formation, the biological consequences of their formation in cancer and evidence suggesting that APOBEC mutagenesis can also occur genome-wide. This raises the possibility that dysregulation of these enzymes may enable rapid malignant transformation by increasing mutation rates without the loss of fitness associated with permanent mutators. © 2014 WILEY Periodicals, Inc. Source


Birnbaum L.S.,National Health Research Institute | Jung P.,National Institute of Environmental Health and Safety
Health Affairs | Year: 2011

Environmental health science is the study of the impact of the environment on human health. This paper introduces basic topics in environmental health, including clean air, clean water, and healthful food, as well as a range of current issues and controversies in environmental health. Conceptual shifts in modern toxicology have changed the field. There is a new understanding of the effects of exposure to chemicals at low doses, and in combination, and the impact on human growth and development. Other emerging topics include the role of epigenetics, or changes in genes and gene expression that can be brought about by chemical exposure; environmental justice; and potential effects of engineered nanomaterials and climate change. We review the important implications for public health policy and recommend a broad environmental health research strategy aimed at protecting and improving human health. © 2011 Project HOPE-The People-to-People Health Foundation, Inc. Source

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