Cloning, Tissue Expression, and Mapping of a Human Photolyase Homolog with Similarity to Plant Blue-Light Receptors

Enzymatic photoreactivation is a DNA repair mechanism that removes UV-induced pyrimidine dimer lesions by action of a single enzyme, photolyase, and visible light. Its presence has been demonstrated in a wide variety of organisms, ranging from simple prokaryotes to higher eukaryotes. We have isolated a human gene encoding a 66-kDa protein that shows clear overall homology to known bacterial photolyase genes. The human gene product is more similar to plant blue-light receptors within class I photolyases than to higher eukaryote class II photolyases. Northern blot analysis showed two transcripts with constitutive expression in all tissues examined and an elevated expression in testis.In situhybridization with a cDNA-derived probe localized this human gene to chromosome 12q23–q24.1. Southern analysis of the cloned human gene suggests a wide distribution of the gene family in various species.