Uracil DNA Glycosylase (UNG)

UNG encodes one of several uracil-DNA glycosylases. One important function of uracil-DNA glycosylases is to prevent mutagenesis by eliminating uracil from DNA molecules by cleaving the N-glycosylic bond and initiating the base-excision repair (BER) pathway. Uracil bases occur from cytosine deamination or misincorporation of dUMP residues. Alternative promoter usage and splicing of this gene leads to two different isoforms: the nuclear (UNG2) and mitochondrial (UNG1) isoforms of UNG result from alternative splicing and the use of alternative promoters. The UNG1 and UNG2 proteins contain different N-terminal sequences, but the downstream 269 amino acids are common and include a short region that binds replication protein A and a larger, compact catalytic domain.