DNA polymerases in the mitochondria: A critical review of the evidence.
Since 1970, the DNA polymerase gamma (PolG) has been known to be the DNA polymerase responsible for replication and repair of mitochondrial DNA, and until recently it was generally accepted that this was the only polymerase present in mitochondria. However, recent data has challenged that opinion, as several polymerases are now proposed to have activity in mitochondria. To date, their exact role of these other DNA polymerases is unclear and the amount of evidence supporting their role in mitochondria varies greatly. Further complicating matters, no universally accepted standards have been set for definitive proof of the mitochondrial localization of a protein. To gain an appreciation of these newly proposed DNA polymerases in the mitochondria, we review the evidence and standards needed to establish the role of a polymerase in the mitochondria. Employing PolG as an example, we established a list of criteria necessary to verify the existence and function of new mitochondrial proteins. We then apply this criteria towards several other putative mitochondrial polymerases. While there is still a lot left to be done in this exciting new direction, it is clear that PolG is not acting alone in mitochondria, opening new doors for potential replication and repair mechanisms.
Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
Rachel
R
Krasich
Genome Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, 111 T.W. Alexander Dr., Bldg. 101, Rm. E316, Research Triangle Park, NC 27709, copelan1@niehs.nih.gov.
William C
WC
Copeland
D000818:Animals; D019951:DNA Polymerase beta / Q000235:genetics / Q000378:metabolism; D000074002:DNA Polymerase gamma / Q000235:genetics / Q000378:metabolism; D019915:DNA Primase / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D028361:Mitochondrial Diseases / Q000201:enzymology / Q000235:genetics; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D064251:Multifunctional Enzymes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D000097462:DNA Polymerase theta; D000099270:Y-Family DNA Polymerases
D019951:DNA Polymerase beta; D000074002:DNA Polymerase gamma; D019915:DNA Primase; D004272:DNA, Mitochondrial; D004268:DNA-Binding Proteins; D004259:DNA-Directed DNA Polymerase; D024101:Mitochondrial Proteins; D064251:Multifunctional Enzymes; D000097462:DNA Polymerase theta; C425929:DNA polymerase zeta; C585901:PrimPol protein, human; C413027:POLG protein, human; C118285:REV3L protein, human; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases