EXO1

This gene encodes a protein with 5' to 3' exonuclease activity as well as an RNase H activity. It is similar to the Saccharomyces cerevisiae protein Exo1 which interacts with Msh2 and which is involved in mismatch repair and recombination. Alternative splicing of this gene results in three transcript variants encoding two different isoforms. [provided by RefSeq, Jul 2008]

Full Name

Exonuclease 1

Research Area

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.

Biological Process

DNA recombination Source: UniProtKB
DNA repair Source: ProtInc
Humoral immune response mediated by circulating immunoglobulin Source: Ensembl
Isotype switching Source: Ensembl
Meiotic cell cycle Source: UniProtKB-KW
Mismatch repair Source: UniProtKB
Somatic hypermutation of immunoglobulin genes Source: Ensembl
T-circle formation Source: BHF-UCL

Cellular Location

Nucleus. Colocalizes with PCNA to discrete nuclear foci in S-phase.

PTM

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.