The DNA pol β is a DNA polymerase involved in base excision and repair, also called gap-filling DNA synthesis. DNA pol β a comprises an amino-terminal 8-kDa domain and a carboxy-terminal 31-kDa domain. The protein, acting as a monomer, is normally found in the cytoplasm, but it translocates to the nucleus upon DNA damage. Mammalian DNA pol β, a DNA repair polymerase, is constitutively expressed in cultured cells, but treatment of cells with the DNA-alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or methyl methanesulfonate up-regulates beta-pol level.
