Search results for POLH

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Pathway (3 results from a total of 3)

Identifier: R-HSA-110320
Species: Homo sapiens
Compartment: nucleoplasm
DNA polymerase eta (POLH) consists of 713 amino acids and can bypass thymidine-thymidine dimers, correctly adding two dAMPs opposite to the lesion. Mutations in the POLH gene result in the loss of this bypass activity and account for the XP variant phenotype (XPV) in human xeroderma pigmentosum disorder patients. POLH can carry out TLS past various UV and chemically induced lesions via two steps: (a) preferential incorporation of correct bases opposite to the lesion (b) conditional elongation only at the sites where such correct bases are inserted (Masutani et al. 1999, Masutani et al. 2000).
Identifier: R-HSA-73893
Species: Homo sapiens
Compartment: nucleoplasm
In addition to various processes for removing lesions from the DNA, cells have developed specific mechanisms for tolerating unrepaired damage during the replication of the genome. These mechanisms are collectively called DNA damage bypass pathways. The Y family of DNA polymerases plays a key role in DNA damage bypass.

Y family DNA polymerases, REV1, POLH (DNA polymerase eta), POLK (DNA polymerase kappa) and POLI (DNA polymerase iota), as well as the DNA polymerase zeta (POLZ) complex composed of REV3L and MAD2L2, are able to carry out translesion DNA synthesis (TLS) or replicative bypass of damaged bases opposite to template lesions that arrest high fidelity, highly processive replicative DNA polymerase complexes delta (POLD) and epsilon (POLE). REV1, POLH, POLK, POLI and POLZ lack 3'->5' exonuclease activity and exhibit low fidelity and weak processivity. The best established TLS mechanisms are annotated here. TLS details that require substantial experimental clarification have been omitted. For recent and past reviews of this topic, please refer to Lehmann 2000, Friedberg et al. 2001, Zhu and Zhang 2003, Takata and Wood 2009, Ulrich 2011, Saugar et al. 2014.

Identifier: R-HSA-110314
Species: Homo sapiens
Compartment: nucleoplasm
Damaged double strand DNA (dsDNA) cannot be successfully used as a template by replicative DNA polymerase delta (POLD) and epsilon (POLE) complexes (Hoege et al. 2002). When the replication complex composed of PCNA, RPA, RFC and POLD or POLE stalls at a DNA damage site, PCNA becomes monoubiquitinated by RAD18 bound to UBE2B (RAD6). POLD or POLE dissociate from monoubiquitinated PCNA, while Y family DNA polymerases - REV1, POLH (DNA polymerase eta), POLK (DNA polymerase kappa) and POLI (DNA polymerase iota) - bind monoubiquitinated PCNA through their ubiquitin binding and PCNA binding motifs, resulting in a polymerase switch and initiation of translesion synthesis (TLS) (Hoege et al. 2002, Friedberg et al. 2005).
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