The mouse uracil-DNA glycosylase gene: isolation of cDNA and genomic clones and mapping ung to mouse chromosome 5.

Uracil-DNA glycosylase (UDG) is the enzyme responsible for the first step in the base-excision repair pathway that specifically removes uracil from DNA. Here we report the isolation of the cDNA and genomic clones for the mouse uracil-DNA glycosylase gene (ung) homologous to the major placental uracil-DNA glycosylase gene (UNG) of humans. The complete characterization of the genomic organization of the mouse uracil-DNA glycosylase gene shows that the entire mRNA coding region for the 1.83-kb cDNA of the mouse ung gene is contained in an 8.2-kb SstI genomic fragment which includes six exons and five introns. The cDNA encodes a predicted uracil-DNA glycosylase (UDG) protein of 295 amino acids (33 kDa) that is highly similar to a group of UDGs that have been isolated from a wide variety of organisms. The mouse ung gene has been mapped to mouse chromosome 5 using fluorescence in situ hybridization (FISH).