DNA polymerase eta

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Protein POLH PDB 2i5o.png
Available structures
PDBOrtholog search: PDBe RCSB
AliasesPOLH, RAD30, RAD30A, XP-V, XPV, DNA polymerase eta, polymerase (DNA) eta
External IDsMGI: 1891457 HomoloGene: 38189 GeneCards: POLH
Gene location (Human)
Chromosome 6 (human)
Chr.Chromosome 6 (human)[1]
Chromosome 6 (human)
Genomic location for POLH
Genomic location for POLH
Band6p21.1Start43,576,150 bp[1]
End43,615,660 bp[1]
RNA expression pattern
PBB GE POLH 219380 x at fs.png
More reference expression data
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 6: 43.58 – 43.62 MbChr 17: 46.17 – 46.2 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

DNA polymerase eta (Pol η), is a protein that in humans is encoded by the POLH gene.[5][6][7]

DNA 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. Polymerase eta is particularly important for allowing accurate translesion synthesis of DNA damage resulting from ultraviolet radiation or UV.


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. However, it accurately replicates UV-damaged DNA; when thymine dimers are present, this polymerase inserts the complementary nucleotides in the newly synthesized DNA, thereby bypassing the lesion and suppressing the mutagenic effect of UV-induced DNA damage. This polymerase is thought to be involved in hypermutation during immunoglobulin class switch recombination.[5]

Bypass of 8-oxoguanine[edit]

During DNA replication of the Saccharomyces cerevisiae chromosome, the oxidative DNA damage 8-oxoguanine triggers a switch to translesion synthesis by DNA polymerase eta.[8] This polymerase replicates 8-oxoguanine with an accuracy (insertion of a cytosine opposite the 8-oxoguanine) of approximately 94%. Replication of 8-oxoguanine in the absence of DNA polymerase eta is less than 40%.

Clinical significance[edit]

Mutations in this gene result in XPV, a variant type of xeroderma pigmentosum, characterized by sun sensitivity, elevated incidence of skin cancer, and at the cellular level, by delayed replication and hypermutability after UV-irradiation[9][10]


POLH has been shown to interact with PCNA.[11]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000170734 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000023953 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:".
  4. ^ "Mouse PubMed Reference:".
  5. ^ a b "Entrez Gene: POLH polymerase (DNA directed), eta".
  6. ^ Masutani C, Kusumoto R, Yamada A, Dohmae N, Yokoi M, Yuasa M, Araki M, Iwai S, Takio K, Hanaoka F (June 1999). "The XPV (xeroderma pigmentosum variant) gene encodes human DNA polymerase eta". Nature. 399 (6737): 700–4. doi:10.1038/21447. PMID 10385124.
  7. ^ Johnson RE, Kondratick CM, Prakash S, Prakash L (July 1999). "hRAD30 mutations in the variant form of xeroderma pigmentosum". Science. 285 (5425): 263–5. doi:10.1126/science.285.5425.263. PMID 10398605.
  8. ^ Rodriguez GP, Song JB, Crouse GF (2013). "In vivo bypass of 8-oxodG". PLoS Genet. 9 (8): e1003682. doi:10.1371/journal.pgen.1003682. PMC 3731214. PMID 23935538.
  9. ^ Stary A, Sarasin A (September 2002). "Molecular mechanisms of UV-induced mutations as revealed by the study of DNA polymerase eta in human cells". Res. Microbiol. 153 (7): 441–5. doi:10.1016/S0923-2508(02)01343-8. PMID 12405351.
  10. ^ Cruet-Hennequart S, Gallagher K, Sokòl AM, Villalan S, Prendergast AM, Carty MP (2010). "DNA polymerase eta, a key protein in translesion synthesis in human cells". Sub-cellular Biochemistry. 50: 189–209. doi:10.1007/978-90-481-3471-7_10. PMID 20012583.
  11. ^ Haracska L, Johnson RE, Unk I, Phillips B, Hurwitz J, Prakash L, Prakash S (November 2001). "Physical and functional interactions of human DNA polymerase eta with PCNA". Mol. Cell. Biol. 21 (21): 7199–206. doi:10.1128/MCB.21.21.7199-7206.2001. PMC 99895. PMID 11585903.

Further reading[edit]

External links[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.