Eukaryotic DNA polymerase
Encyclopedia
There are at least 15 Eukaryotic DNA polymerases:
None of the eukaryotic polymerases can remove primers (5'->3' exonuclease activity); that function is carried out by other enzymes. Only the polymerases that deal with the elongation (γ, δ and ε) have proofreading ability (3'->5' exonuclease).
- POLA1POLA1DNA polymerase alpha catalytic subunit is an enzyme that in humans is encoded by the POLA1 gene.Pol α has limited processivity and lacks 3′ exonuclease activity for proofreading errors. Thus it is not well suited to efficiently and accurately copy long templates . Instead it plays a more limited...
, POLA2POLA2DNA polymerase alpha subunit B is an enzyme that in humans is encoded by the POLA2 gene.-Further reading:...
: Pol α (also called RNA primase): forms a complex with a small catalytic (PriS) and a large noncatalytic (PriL) subunit, with the Pri subunits acting as a primase (synthesizing an RNA primer), and then with DNA Pol α elongating that primer with DNA nucleotides. After around 20 nucleotides elongation is taken over by Pol ε (on the leading strand) and δ (on the lagging strand).
- POLB: Pol βDNA polymerase beta[edit]Polymerase , beta, also known as POLB, is an enzyme that, in humans, is encoded by the POLB gene.- Function :...
: Implicated in repairing DNA, in base excision repair and gap-filling synthesis.
- POLGPOLGDNA polymerase subunit gamma is an enzyme that in humans is encoded by the POLG gene.-Functions:POLG is the gene that codes for the catalytic subunit of the mitochondrial DNA polymerase, called DNA polymerase gamma . The human POLG cDNA and gene were originally cloned mapped to chromosome 15,...
, POLG2POLG2DNA polymerase subunit gamma-2, mitochondrial is an protein that in humans is encoded by the POLG2 gene. The POLG2 gene encodes a 55 kDa accessory subunit protein that imparts high processivity and salt tolerance to the catalytic subunit of DNA polymerase gamma, encoded by the POLG gene. -Further...
: Pol γ: Replicates and repairs mitochondrial DNAMitochondrial DNAMitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
and has proofreading 3'->5' exonuclease activity.
- POLD1POLD1DNA polymerase delta catalytic subunit is an enzyme that in humans is encoded by the POLD1 gene. It is a component of the DNA polymerase delta complex.-Further reading:...
, POLD2POLD2DNA polymerase delta subunit 2 is an enzyme that in humans is encoded by the POLD2 gene. It is a component of the DNA polymerase delta complex.-Further reading:...
, POLD3POLD3DNA polymerase delta subunit 3 is an enzyme that in humans is encoded by the POLD3 gene. It is a component of the DNA polymerase delta complex.-Further reading:...
, POLD4POLD4DNA polymerase delta subunit 4, also known as DNA polymerase delta subunit p12, is a protein that in humans is encoded by the POLD4 gene. It is a component of the DNA polymerase delta complex....
: Pol δDNA polymerase deltaDNA polymerase delta is an enzyme complex found in eukaryotes that is involved in DNA replication and repair, and it consists of the proliferating cell nuclear antigen , the multisubunit replication factor C, and the 4 subunit polymerase complex: POLD1, POLD2, POLD3, and POLD4....
: Highly processive and has proofreading 3'->5' exonuclease activity. Thought to be the main polymerase involved in lagging strand synthesis, though there is still debate about its role.
- POLEPOLEDNA polymerase epsilon catalytic subunit A is an enzyme that in humans is encoded by the POLE gene.-Further reading:...
, POLE2POLE2DNA polymerase epsilon subunit 2 is an enzyme that in humans is encoded by the POLE2 gene.-Further reading:...
, POLE3POLE3DNA polymerase epsilon subunit 3 is an enzyme that in humans is encoded by the POLE3 gene.-Further reading:...
: Pol ε: Also highly processive and has proofreading 3'->5' exonuclease activity. Highly related to pol δ, and thought to be the main polymerase involved in leading strand synthesis, though there is again still debate about its role.
- POLHPOLHPolymerase , eta, also known as POLH, is a protein which in humans is encoded by the POLH gene.-Function:This gene encodes a member of the Y family of specialized DNA polymerases. It copies undamaged DNA with a lower fidelity than other DNA-directed polymerases...
, POLIPOLIDNA polymerase iota is an enzyme that in humans is encoded by the POLI gene. It is found in higher eukaryotes, and is believed to have arisen from a gene duplication from Pol η. Pol ι, is a Y family polymerase that is involved in translesion synthesis. It can bypass 6-4 pyrimidine adducts and...
, POLKPOLKDNA polymerase kappa is an enzyme that in humans is encoded by the POLK gene.-Further reading:...
, : ηDNA polymerase etaDNA polymerase eta is a eukaryotic DNA polymerase involved in the DNA repair by translesion synthesis. The gene encoding DNA polymerase eta is POLH, also known as XPV, because loss of this gene results in the disease Xeroderma Pigmentosum Variant...
, ι, κPOLKDNA polymerase kappa is an enzyme that in humans is encoded by the POLK gene.-Further reading:...
, and Rev1 are Y-family DNA polymerases and Pol ζ is a B-family DNA polymerase. These polymerases are involved in the bypass of DNA damage.
- There are also other eukaryotic polymerases known, which are not as well characterized:
- POLQPOLQDNA polymerase theta is an enzyme that in humans is encoded by the POLQ gene.-Further reading:...
: θ - POLLPOLLDNA polymerase lambda, also known as POLL, is a protein that, in humans, is encoded by the POLLA gene.- Function :Pol λ is a member of the X family of DNA polymerases. It is thought to resynthesize missing nucleotides during non-homologous end joining, a pathway of DNA double-strand break repair...
: λ - ?: φ
- ?: σ
- POLMPOLMDNA polymerase mu is a human protein encoded by the POLM gene.-Function:Pol μ is a member of the X family of DNA polymerases. It participates in resynthesis of damaged or missing nucleotides during the non-homologous end joining pathway of DNA repair. Pol μ interacts with Ku and DNA ligase IV,...
: μ
- POLQ
None of the eukaryotic polymerases can remove primers (5'->3' exonuclease activity); that function is carried out by other enzymes. Only the polymerases that deal with the elongation (γ, δ and ε) have proofreading ability (3'->5' exonuclease).