EXO1
Developmental stage
Highly expressed in fetal liver and at lower levels in fetal brain, heart, kidney, spleen and thymus.
Function
5'->3' double-stranded DNA exonuclease which may also possess a cryptic 3'->5' double-stranded DNA exonuclease activity. Functions in DNA mismatch repair (MMR) to excise mismatch-containing DNA tracts directed by strand breaks located either 5' or 3' to the mismatch. Also exhibits endonuclease activity against 5'-overhanging flap structures similar to those generated by displacement synthesis when DNA polymerase encounters the 5'-end of a downstream Okazaki fragment. Required for somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin genes. Essential for male and female meiosis.
Post-translational modifications
Phosphorylated upon DNA damage and in response to agents stalling DNA replication, probably by ATM or ATR. Phosphorylation at Ser-454, Thr-621 and Ser-714 is induced upon DNA-damage caused by treatment with hydroxyurea (HU) but not upon IR treatment. The HU-induced EXO1 triple phosphorylation facilitates destabilization/degradation of the protein.
Sequence Similarities
Belongs to the XPG/RAD2 endonuclease family. EXO1 subfamily.
Tissue Specificity
Highly expressed in bone marrow, testis and thymus. Expressed at lower levels in colon, lymph nodes, ovary, placenta, prostate, small intestine, spleen and stomach.
Cellular localization
- Nucleus
- Colocalizes with PCNA to discrete nuclear foci in S-phase.
Alternative names
EXOI, HEX1, EXO1, Exonuclease 1, hExo1, Exonuclease I, hExoI