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PMID: 19625489 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

The accessory subunit of mitochondrial DNA polymerase gamma determines the DNA content of mitochondrial nucleoids in human cultured cells.

Nucleic acids research ·Vol. 37 ·No. 17 ·2009-09-00 ·Pages 5701-13

Di Re M, Sembongi H, He J, Reyes A, Yasukawa T, Martinsson P, Bailey LJ, Goffart S, Boyd-Kirkup JD, Wong TS, Fersht AR, Spelbrink JN, Holt IJ

Abstract

The accessory subunit of mitochondrial DNA polymerase gamma, POLGbeta, functions as a processivity factor in vitro. Here we show POLGbeta has additional roles in mitochondrial DNA metabolism. Mitochondrial DNA is arranged in nucleoprotein complexes, or nucleoids, which often contain multiple copies of the mitochondrial genome. Gene-silencing of POLGbeta increased nucleoid numbers, whereas over-expression of POLGbeta reduced the number and increased the size of mitochondrial nucleoids. Both increased and decreased expression of POLGbeta altered nucleoid structure and precipitated a marked decrease in 7S DNA molecules, which form short displacement-loops on mitochondrial DNA. Recombinant POLGbeta preferentially bound to plasmids with a short displacement-loop, in contrast to POLGalpha. These findings support the view that the mitochondrial D-loop acts as a protein recruitment centre, and suggest POLGbeta is a key factor in the organization of mitochondrial DNA in multigenomic nucleoprotein complexes.

MeSH Terms
Cell Line, Tumor DNA Polymerase gamma DNA, Mitochondrial/analysis,chemistry,metabolism DNA-Directed DNA Polymerase/genetics,metabolism Humans Mitochondria/enzymology,ultrastructure Nucleic Acid Synthesis Inhibitors Nucleoproteins/metabolism Plasmids/chemistry Protein Subunits/antagonists & inhibitors,genetics,metabolism RNA Interference
Chemicals
DNA, Mitochondrial Nucleic Acid Synthesis Inhibitors Nucleoproteins Protein Subunits DNA Polymerase gamma DNA-Directed DNA Polymerase POLG2 protein, human
Authors & Affiliations
13 authors, click to expand affiliations / ORCID
Di Re M
MRC-Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.
Sembongi H
He J
Reyes A
Yasukawa T
Martinsson P
Bailey L J
Goffart S
Boyd-Kirkup J D
Wong T S
Fersht A R
Spelbrink J N
Holt I J
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Article Info
Journal
Nucleic acids research
Abbr.
Nucleic Acids Res
ISSN
1362-4962
DOI
10.1093/nar/gkp614
Published
2009-09-00
Epub
2009-00-22
Pages
5701-13
Language
English
Region
England
NLM ID
0411011
PMCID
PMC2761280
Subset
IM
Grants
Medical Research Council · MC_U105474168 · United Kingdom
Medical Research Council · MC_U105663140 · United Kingdom
External Links
PubMed source DOI: 10.1093/nar/gkp614 PMC Full Text View journal details
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