Excises uracil residues from the DNA which can arise as a result of misincorporation of dUMP residues by DNA polymerase or due to deamination of cytosine. Also part of a heterodimeric processivity factor which potentiates the DNA polymerase activity. Binds to DNA (By similarity). Hydrolyzes single-stranded DNA or mismatched double-stranded DNA and polynucleotides, releasing free uracil. Homodimer. Interacts with protein A20. Component of the Uracil-DNA glycosylase(UDG)-A20-polymerase complex; A20 and UDG form a heterodimeric processivity factor that associates with E9 to form the processive polymerase holoenzyme (By similarity). Belongs to the uracil-DNA glycosylase (UDG) superfamily. UNG family.