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PMID: 19487465 Published · ppublish English Journal Article

Human Dna2 is a nuclear and mitochondrial DNA maintenance protein.

Molecular and cellular biology ·Vol. 29 ·No. 15 ·2009-08-00 ·Pages 4274-82

Duxin JP, Dao B, Martinsson P, Rajala N, Guittat L, Campbell JL, Spelbrink JN, Stewart SA

Abstract

Dna2 is a highly conserved helicase/nuclease that in yeast participates in Okazaki fragment processing, DNA repair, and telomere maintenance. Here, we investigated the biological function of human Dna2 (hDna2). Immunofluorescence and biochemical fractionation studies demonstrated that hDna2 was present in both the nucleus and the mitochondria. Analysis of mitochondrial hDna2 revealed that it colocalized with a subfraction of DNA-containing mitochondrial nucleoids in unperturbed cells. Upon the expression of disease-associated mutant forms of the mitochondrial Twinkle helicase which induce DNA replication pausing/stalling, hDna2 accumulated within nucleoids. RNA interference-mediated depletion of hDna2 led to a modest decrease in mitochondrial DNA replication intermediates and inefficient repair of damaged mitochondrial DNA. Importantly, hDna2 depletion also resulted in the appearance of aneuploid cells and the formation of internuclear chromatin bridges, indicating that nuclear hDna2 plays a role in genomic DNA stability. Together, our data indicate that hDna2 is similar to its yeast counterpart and is a new addition to the growing list of proteins that participate in both nuclear and mitochondrial DNA maintenance.

MeSH Terms
Blotting, Western Cell Line Cell Nucleus/genetics,metabolism Cytoplasm/metabolism DNA Damage DNA Helicases/genetics,metabolism DNA Repair DNA Replication/genetics DNA, Mitochondrial/genetics Fluorescent Antibody Technique HeLa Cells Humans Immunoprecipitation Microscopy, Confocal Mitochondria/metabolism Mitochondrial Proteins Mutation RNA Interference
Chemicals
DNA, Mitochondrial Mitochondrial Proteins DNA Helicases DNA2 protein, human TWNK protein, human
Authors & Affiliations
8 authors, click to expand affiliations / ORCID
Duxin Julien P
Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
Dao Benjamin
Martinsson Peter
Rajala Nina
Guittat Lionel
Campbell Judith L
Spelbrink Johannes N
Stewart Sheila A
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Article Info
Journal
Molecular and cellular biology
Abbr.
Mol Cell Biol
ISSN
1098-5549
DOI
10.1128/MCB.01834-08
Published
2009-08-00
Epub
2009-00-01
Pages
4274-82
Language
English
Region
United States
NLM ID
8109087
PMCID
PMC2715806
Subset
IM
External Links
PubMed source DOI: 10.1128/MCB.01834-08 PMC Full Text View journal details
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