Background and aim: Exonuclease1 (EXO1) is a member of the RAD2 nuclease family which is involved in mismatch repair (MMR) system and contributes to the maintenance of genomic stability, modulation of DNA recombination and cell cycle arrest mediation. K589E (rs1047840) as a potentially functional polymorphism in EXO1 gene may alter cancer risk by influencing its repair activity. Method: We desi...

Replication is not as continuous as once thought, with DNA damage frequently stalling replication forks. Aberrant repair of stressed replication forks can result in cell death or genome instability and resulting transformation to malignancy. Stressed replication forks are most commonly repaired via homologous recombination (HR), which begins with 5' end resection, mediated by exonuclease comple...

Alkylation-induced O(6)-methylguanine (O(6)MeG) DNA lesions can be mutagenic or cytotoxic if unrepaired by the O(6)MeG-DNA methyltransferase (Mgmt) protein. O(6)MeG pairs with T during DNA replication, and if the O(6)MeG:T mismatch persists, a G:C to A:T transition mutation is fixed at the next replication cycle. O(6)MeG:T mismatch detection by MutSalpha and MutLalpha leads to apoptotic cell de...

We previously described a 5'-3' exonuclease required for recombination in vitro between linear DNA molecules with overlapping homologous ends. This exonuclease, referred to as exonuclease I (Exo I), has been purified more than 300-fold from vegetatively grown cells and copurifies with a 42-kDa polypeptide. The activity is nonprocessive and acts preferentially on double-stranded DNA. The biochem...

Single-stranded DNA (ssDNA) at DNA ends is an important regulator of the DNA damage response. Resection, the generation of ssDNA, affects DNA damage checkpoint activation, DNA repair pathway choice, ssDNA-associated mutation and replication fork stability. In eukaryotes, extensive DNA resection requires the nuclease Exo1 and nuclease/helicase pair: Dna2 and Sgs1(BLM). How Exo1 and Dna2-Sgs1(BLM...

The Mre11-Rad50-Nbs1(Xrs2) complex and the Ku70-Ku80 heterodimer are thought to compete with each other for binding to DNA ends. To investigate the mechanism underlying this competition, we analyzed both DNA damage sensitivity and telomere overhangs in Schizosaccharomyces pombe rad50-d, rad50-d pku70-d, rad50-d exo1-d, and pku70-d rad50-d exo1-d cells. We found that rad50 exo1 double mutants ar...

Dna2 was first characterized in yeast as an essential gene encoding a protein with both helicase and endonuclease activities involved in maturation of Okazaki fragments during DNA replication. Dna2 also plays a role in double-strand break (DSB) repair by homolo-gous recombination. The respective contributions of its replication and/or repair functions toward cell viability and resistance to gen...

Dna2 was first characterized in yeast as an essential gene encoding a protein with both helicase and endonuclease activities involved in maturation of Okazaki fragments during DNA replication. Dna2 also plays a role in double-strand break (DSB) repair by homolo-gous recombination. The respective contributions of its replication and/or repair functions toward cell viability and resistance to gen...

Dna2 was first characterized in yeast as an essential gene encoding a protein with both helicase and endonuclease activities involved in maturation of Okazaki fragments during DNA replication. Dna2 also plays a role in double-strand break (DSB) repair by homolo-gous recombination. The respective contributions of its replication and/or repair functions toward cell viability and resistance to gen...