The Caenorhabditis elegans gene CeAPN1 encodes a homolog of Escherichia coli and yeast apurinic/apyrimidinic endonuclease.

The Saccharomyces cerevisiae APN1 gene, encoding the bifunctional DNA repair enzyme apurinic/apyrimidinic (AP) endonuclease/3'-repair diesterase, was used as a probe to isolate a gene homolog, CeAPN1, from a Caenorhabditis elegans cDNA library. The CeAPN1 gene is predicted to encode a protein 30 kDa in size, which shares 40.4% and 44.9% identity at the amino acid level with, respectively, S. cerevisiae Apn1 and Escherichia coli endonuclease IV. We suggest that CeApn1 protein is a member of the endonuclease IV family of DNA repair enzymes.