TREX2

Three prime repair exonuclease 2 is an enzyme that in humans is encoded by the TREX2 gene.^[5][6]

TREX2
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1Y97
Identifiers
Aliases	TREX2, three prime repair exonuclease 2
External IDs	OMIM: 300370; MGI: 1346343; HomoloGene: 8046; GeneCards: TREX2; OMA:TREX2 - orthologs
Gene location (Human) Chr. X chromosome (human)[1] Band Xq28 Start 153,444,473 bp[1] End 153,470,587 bp[1]
Gene location (Mouse) Chr. X chromosome (mouse)[2] Band X|X A7.3 Start 72,477,311 bp[2] End 72,478,950 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in skin of abdomen skin of leg ascending aorta Descending thoracic aorta right coronary artery tibial arteries granulocyte left coronary artery ectocervix spleen Top expressed in esophagus lip embryo embryo skin of external ear skin of abdomen submandibular gland skin of back stomach umbilical cord More reference expression data BioGPS n/a
Gene ontology Molecular function nuclease activity exodeoxyribonuclease III activity exonuclease activity hydrolase activity protein homodimerization activity magnesium ion binding 3'-5'-exodeoxyribonuclease activity metal ion binding nucleic acid binding 3'-5' exonuclease activity Cellular component nucleus Biological process DNA repair cellular response to DNA damage stimulus nucleic acid phosphodiester bond hydrolysis DNA metabolic process Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 11219 24102 Ensembl ENSG00000183479 ENSMUSG00000031372 UniProt Q9BQ50 Q9R1A9 RefSeq (mRNA) NM_080701 NM_080699 NM_080700 NM_011907 RefSeq (protein) NP_542432 NP_036037 Location (UCSC) Chr X: 153.44 – 153.47 Mb Chr X: 72.48 – 72.48 Mb PubMed search [3] [4]
Wikidata
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This gene encodes a protein with 3' exonuclease activity. Enzymes with this activity are involved in DNA replication, repair, and recombination. Similarity to an E. coli protein suggests that this enzyme may be a subunit of DNA polymerase III, which does not have intrinsic exonuclease activity.^[6]

Newer research has determined that TREX2 is also involved in flap endonuclease activity, as detected in the context of inhibiting gene-editing nickases that generate an extension flap such as prime editors that do not usually create a double-stranded break. This function was first demonstrated in a thesis by Lung in 2021,^[7] and replicated by Koeppel et al. in 2023.^[8] Subsequently, TREX2 has become incorporated into fusion enzymes for genetic engineering by multiple research groups for the purposes of reducing off-target edits which include chromosomal translocations and mismatched insertions.^[9][10]

Mutations in this gene may lead to Aicardi-Goutieres syndrome.