| Polymerase (DNA directed), mu | |||||||||||||
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 PDB rendering based on 2dun. |
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| Identifiers | |||||||||||||
| Symbols | POLM; Pol Mu; Tdt-N | ||||||||||||
| External IDs | OMIM: 606344 MGI: 1860191 HomoloGene: 41170 GeneCards: POLM Gene | ||||||||||||
| EC number | 2.7.7.7 | ||||||||||||
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| Orthologs | |||||||||||||
| Species | Human | Mouse | |||||||||||
| Entrez | 27434 | 54125 | |||||||||||
| Ensembl | ENSG00000122678 | ENSMUSG00000020474 | |||||||||||
| UniProt | Q9NP87 | Q9JIW4 | |||||||||||
| RefSeq (mRNA) | NM_013284.2 | NM_017401.2 | |||||||||||
| RefSeq (protein) | NP_037416.1 | NP_059097.2 | |||||||||||
| Location (UCSC) | Chr 7: 44.11 – 44.12 Mb |
Chr 11: 5.73 – 5.74 Mb |
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| PubMed search | [1] | [2] | |||||||||||
DNA polymerase mu is a human protein encoded by the POLM gene.[1]
Function [link]
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 (NHEJ) pathway of DNA repair.[2] Pol μ interacts with Ku and DNA ligase IV, which also participate in NHEJ.[3] It is structurally and functionally related to pol λ, and, like pol λ, pol μ has a BRCT domain that is thought to mediate interactions with other DNA repair proteins.[4] Unlike pol λ, however, pol μ has the unique ability to add a base to a blunt end that is templated by the overhang on the opposite end of the double-strand break.[5] Pol μ is also closely related to terminal deoxynucleotidyl transferase (TdT), a specialized DNA polymerase that adds random nucleotides to DNA ends during V(D)J recombination, the process by which B-cell and T-cell receptor diversity is generated in the vertebrate immune system. Like TdT, pol μ participates in V(D)J recombination, but only during heavy chain rearrangements.[6] This is distinct from pol λ, which is involved in light chain rearrangements.[7]
References [link]
- ^ "Entrez Gene: POLM polymerase (DNA directed), mu". https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=27434.
- ^ Daley JM, Laan RL, Suresh A, Wilson TE (August 2005). "DNA joint dependence of pol X family polymerase action in nonhomologous end joining". J. Biol. Chem. 280 (32): 29030–7. DOI:10.1074/jbc.M505277200. PMID 15964833.
- ^ Mahajan KN, Nick McElhinny SA, Mitchell BS, Ramsden DA (July 2002). "Association of DNA polymerase mu (pol mu) with Ku and ligase IV: role for pol mu in end-joining double-strand break repair". Mol. Cell. Biol. 22 (14): 5194–202. DOI:10.1128/MCB.22.14.5194-5202.2002. PMC 139779. PMID 12077346. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=139779.
- ^ Nick McElhinny SA, Ramsden DA (August 2004). "Sibling rivalry: competition between Pol X family members in V(D)J recombination and general double strand break repair". Immunol. Rev. 200: 156–64. DOI:10.1111/j.0105-2896.2004.00160.x. PMID 15242403.
- ^ Nick McElhinny SA, Havener JM, Garcia-Diaz M, et al. (August 2005). "A gradient of template dependence defines distinct biological roles for family X polymerases in nonhomologous end joining". Mol. Cell 19 (3): 357–66. DOI:10.1016/j.molcel.2005.06.012. PMID 16061182.
- ^ Bertocci B, De Smet A, Berek C, Weill JC, Reynaud CA (August 2003). "Immunoglobulin kappa light chain gene rearrangement is impaired in mice deficient for DNA polymerase mu". Immunity 19 (2): 203–11. DOI:10.1016/S1074-7613(03)00203-6. PMID 12932354.
- ^ Bertocci B, De Smet A, Weill JC, Reynaud CA (July 2006). "Nonoverlapping functions of DNA polymerases mu, lambda, and terminal deoxynucleotidyltransferase during immunoglobulin V(D)J recombination in vivo". Immunity 25 (1): 31–41. DOI:10.1016/j.immuni.2006.04.013. PMID 16860755.
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This article on a gene on chromosome 7 is a stub. You can help Wikipedia by expanding it. |
https://wn.com/DNA_polymerase_mu
DNA polymerase
The DNA polymerases are enzymes that create DNA molecules by assembling nucleotides, the building blocks of DNA. These enzymes are essential to DNA replication and usually work in pairs to create two identical DNA strands from a single original DNA molecule. During this process, DNA polymerase “reads” the existing DNA strands to create two new strands that match the existing ones.
Every time a cell divides, DNA polymerase is required to help duplicate the cell’s DNA, so that a copy of the original DNA molecule can be passed to each of the daughter cells. In this way, genetic information is transmitted from generation to generation.
Before replication can take place, an enzyme called helicase unwinds the DNA molecule from its tightly woven form. This opens up or “unzips” the double-stranded DNA to give two single strands of DNA that can be used as templates for replication.
History
In 1956, Arthur Kornberg and colleagues discovered the enzyme DNA polymerase I, also known as Pol I, in Escherichia coli. They described the DNA replication process by which DNA polymerase copies the base sequence of a template DNA strand. Subsequently, in 1959, Kornberg was awarded the Nobel Prize in Physiology or Medicine for this work.DNA polymerase II was also discovered by Kornberg and Malcolm E. Gefter in 1970 while further elucidating the role of Pol I in E. coli DNA replication.
Φ29 DNA polymerase
Φ29 DNA polymerase is an enzyme from the bacteriophage Φ29. It is being increasingly used in molecular biology for multiple displacement DNA amplification procedures, and has a number of features that make it particularly suitable for this application.
Φ29 DNA replication
Φ29 is a bacteriophage of Bacillus subtilis with a sequenced, linear, 19,285 base pair DNA genome. Each 5' end is covalently linked to a terminal protein, which is essential in the replication process. A symmetrical mode of replication has been suggested, whereby protein-primed initiation occurs non-simultaneously from either end of the chromosome; this involves two replication origins and two distinct polymerase monomers. Synthesis is continual and involves a strand displacement mechanism. This was demonstrated by the ability of the enzyme to continue to copy the singly primed circular genome of the M13 phage more than tenfold in a single strand (over 70kb in a single strand). In vitro experiments have shown that Φ29 replication can proceed to completion with the sole phage protein requirements of the polymerase and the terminal protein. The polymerase catalyses the formation of the initiation complex between the terminal protein and the chromosome ends at an adenine residue. From here, continual synthesis can occur.
DNA polymerase alpha
DNA polymerase alpha also known as Pol α is an enzyme complex found in eukaryotes that is involved in initiation of DNA replication. The DNA polymerase alpha complex consists of 4 subunits: POLA1, POLA2, PRIM1, and PRIM2.
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 (unlike Pol Delta and Epsilon). Instead it plays a more limited role in replication. Pol α is responsible for the initiation of DNA replication at origins of replication (on both the leading and lagging strands) and during synthesis of Okazaki fragments on the lagging strand. The Pol α complex (pol α-DNA primase complex) consists of four subunits: the catalytic subunit POLA1, the regulatory subunit POLA2, and the small and the large primase subunits PRIM1 and PRIM2 respectively. Once primase has created the RNA primer, Pol α starts replication elongating the primer with ~20 nucleotides.
