DNA polymerase gamma, catalytic subunit
Last updated 20 Sept 2023
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The POLG gene provides instructions for making the active piece, called the alpha subunit, of a protein called polymerase gamma (pol γ). To be most effective, the alpha subunit attaches to two copies of another protein called the beta subunit to form pol γ. Pol γ is a DNA polymerase, which is a type of enzyme that "reads" sequences of DNA and uses them as templates to produce new DNA. These enzymes are important for copying (replicating) cells' genetic material. DNA polymerases also play critical roles in DNA repair.
Normal function
The POLG gene provides instructions for making the active piece, called the alpha subunit, of a protein called polymerase gamma (pol γ). To be most effective, the alpha subunit attaches to two copies of another protein called the beta subunit to form pol γ. Pol γ is a DNA polymerase, which is a type of enzyme that "reads" sequences of DNA and uses them as templates to produce new DNA. These enzymes are important for copying (replicating) cells' genetic material. DNA polymerases also play critical roles in DNA repair.
Pol γ functions in mitochondria. Mitochondria are structures within cells in which a process called oxidative phosphorylation converts the energy from food into a form that cells can use. Mitochondria each contain a small amount of DNA, known as mitochondrial DNA (mtDNA), which is essential for the normal function of these structures. Pol γ is the only DNA polymerase that is active in mitochondria and that can replicate mtDNA.
Conditions referring to this gene or chromosome
Other names
DNA polymerase subunit gamma-1
mitochondrial DNA polymerase catalytic subunit
PolG, catalytic subunit
PolG-alpha
POLG1
POLGA
polymerase (DNA directed), gamma
polymerase (DNA) gamma, catalytic subunit
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Further reading and references
- DNA polymerase gamma, catalytic subunit; MedlinePlus, National Library of Medicine.
- Chan SS, Longley MJ, Copeland WC. The common A467T mutation in the human mitochondrial DNA polymerase (POLG) compromises catalytic efficiency and interaction with the accessory subunit. J Biol Chem. 2005 Sep 9;280(36):31341-6. doi: 10.1074/jbc.M506762200. Epub 2005 Jul 16.
- Milone M, Massie R. Polymerase gamma 1 mutations: clinical correlations. Neurologist. 2010 Mar;16(2):84-91. doi: 10.1097/NRL.0b013e3181c78a89.
- Moraes CT, Shanske S, Tritschler HJ, Aprille JR, Andreetta F, Bonilla E, Schon EA, DiMauro S. mtDNA depletion with variable tissue expression: a novel genetic abnormality in mitochondrial diseases. Am J Hum Genet. 1991 Mar;48(3):492-501.
- Rajakulendran S, Pitceathly RD, Taanman JW, Costello H, Sweeney MG, Woodward CE, Jaunmuktane Z, Holton JL, Jacques TS, Harding BN, Fratter C, Hanna MG, Rahman S. A Clinical, Neuropathological and Genetic Study of Homozygous A467T POLG-Related Mitochondrial Disease. PLoS One. 2016 Jan 6;11(1):e0145500. doi: 10.1371/journal.pone.0145500. eCollection 2016.
- Rocher C, Taanman JW, Pierron D, Faustin B, Benard G, Rossignol R, Malgat M, Pedespan L, Letellier T. Influence of mitochondrial DNA level on cellular energy metabolism: implications for mitochondrial diseases. J Bioenerg Biomembr. 2008 Apr;40(2):59-67. doi: 10.1007/s10863-008-9130-5. Epub 2008 Apr 16.
- Sohl CD, Kasiviswanathan R, Copeland WC, Anderson KS. Mutations in human DNA polymerase gamma confer unique mechanisms of catalytic deficiency that mirror the disease severity in mitochondrial disorder patients. Hum Mol Genet. 2013 Mar 15;22(6):1074-85. doi: 10.1093/hmg/dds509. Epub 2012 Dec 3.
- Stumpf JD, Copeland WC. Mitochondrial DNA replication and disease: insights from DNA polymerase gamma mutations. Cell Mol Life Sci. 2011 Jan;68(2):219-33. doi: 10.1007/s00018-010-0530-4. Epub 2010 Oct 8.
- Van Goethem G, Dermaut B, Lofgren A, Martin JJ, Van Broeckhoven C. Mutation of POLG is associated with progressive external ophthalmoplegia characterized by mtDNA deletions. Nat Genet. 2001 Jul;28(3):211-2. doi: 10.1038/90034.
- Van Goethem G, Martin JJ, Dermaut B, Lofgren A, Wibail A, Ververken D, Tack P, Dehaene I, Van Zandijcke M, Moonen M, Ceuterick C, De Jonghe P, Van Broeckhoven C. Recessive POLG mutations presenting with sensory and ataxic neuropathy in compound heterozygote patients with progressive external ophthalmoplegia. Neuromuscul Disord. 2003 Feb;13(2):133-42. doi: 10.1016/s0960-8966(02)00216-x.
- Van Goethem G, Martin JJ, Van Broeckhoven C. Progressive external ophthalmoplegia characterized by multiple deletions of mitochondrial DNA: unraveling the pathogenesis of human mitochondrial DNA instability and the initiation of a genetic classification. Neuromolecular Med. 2003;3(3):129-46. doi: 10.1385/NMM:3:3:129.
- Yu Wai Man CY, Chinnery PF, Griffiths PG. Extraocular muscles have fundamentally distinct properties that make them selectively vulnerable to certain disorders. Neuromuscul Disord. 2005 Jan;15(1):17-23. doi: 10.1016/j.nmd.2004.10.002. Epub 2004 Nov 26.
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