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For other uses, see Poli (disambiguation).
Polymerase (DNA directed) iota
Protein POLI PDB 1t3n.png
PDB rendering based on 1t3n.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols POLI ; RAD30B; RAD3OB
External IDs OMIM605252 MGI1347081 HomoloGene5209 ChEMBL: 5391 GeneCards: POLI Gene
EC number
RNA expression pattern
PBB GE POLI 219317 at tn.png
More reference expression data
Species Human Mouse
Entrez 11201 26447
Ensembl ENSG00000101751 ENSMUSG00000038425
UniProt Q9UNA4 Q6R3M4
RefSeq (mRNA) NM_007195 NM_001136090
RefSeq (protein) NP_009126 NP_001129562
Location (UCSC) Chr 18:
51.8 – 51.85 Mb
Chr 18:
70.51 – 70.53 Mb
PubMed search [1] [2]

DNA polymerase iota is an enzyme that in humans is encoded by the POLI gene.[1] 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 abasic sites and has a high frequency of wrong base incorporation. Like many other Y family polymerases Pol ι, has low processivity, a large DNA binding pocket and doesn't undergo conformational changes when DNA binds. These attributes are what allow Pol ι to carry out its task as a translesion polymerase. Pol ι only uses Hoogsteen base pairing, during DNA synthesis, it will add adenine opposite to thymine in the syn conformation and can add both cytosine and thymine in the anti conformation across guanine, which it flips to the syn conformation.


  1. ^ Frank EG, Woodgate R (Aug 2007). "Increased catalytic activity and altered fidelity of human DNA polymerase iota in the presence of manganese". J Biol Chem 282 (34): 24689–96. doi:10.1074/jbc.M702159200. PMID 17609217. 

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