A new class of DNA photolyases present in various organisms including aplacental mammals.

Abstract

DNA photolyase specifically repairs UV light‐induced cyclobutane‐type pyrimidine dimers in DNA through a light‐dependent reaction mechanism. We have obtained photolyase genes from Drosophila melanogaster (fruit fly), Oryzias latipes (killifish) and the marsupial Potorous tridactylis (rat kangaroo), the first photolyase gene cloned from a mammalian species. The deduced amino acid sequences of these higher eukaryote genes show only limited homology with microbial photolyase genes. Together with the previously cloned Carassius auratus (goldfish) gene they form a separate group of photolyase genes. A new classification for photolyases comprising two distantly related groups is proposed. For functional analysis P.tridactylis photolyase was expressed and purified as glutathione S‐transferase fusion protein from Escherichia coli cells. The biologically active protein contained FAD as light‐absorbing cofactor, a property in common with the microbial class photolyases. Furthermore, we found in the archaebacterium Methanobacterium thermoautotrophicum a gene similar to the higher eukaryote photolyase genes, but we could not obtain evidence for the presence of a homologous gene in the human genome. Our results suggest a divergence of photolyase genes in early evolution.

UV Light-induced DNA Damage and Tolerance for the Survival of Nucleotide Excision Repair-deficient Human Cells

“…Cells were cultured in Eagle's minimum essential medium containing 10% fetal calf serum. For the expression of photolyase genes in the XP-A cell line, the cDNA of a CPD photolyase gene (CPDphr) derived from the rat kangaroo P. tridactylis (11) and the cDNA of a 6-4PP photolyase gene (6-4PPphr) derived from A. thaliana (12) were used. Because the A. thaliana gene contains putative signal sequences for transport into mitochondria and chloroplasts at the amino-terminal region, 2 57 nucleotides encoding 19 amino acids from the putative start codon were deleted in the expression construct.…”

“…The light used for illumination was a Toshiba FL20SS fluorescent light, and cells were exposed from the bottom of the dishes through a box made of transparent poly(methyl methacrylate) plate and filled with water to absorb the heat generated by the light. Other illumination conditions have been described previously (11). After illumination, cells were harvested and genomic DNA was extracted using an Easy-DNA kit (Invitrogen).…”

DNA photolyases of Chrysodeixis chalcites nucleopolyhedrovirus are targeted to the nucleus and interact with chromosomes and mitotic spindle structures

“…Photoreactivation is the simplest and fastest DNA repair pathway, and uses only visible light as an energy source and involves a single enzyme, either a CPD or a (6-4)PP photolyase. Photoreactivation occurs in all groups of organisms, except placental mammals, which have to rely on the NER pathway to repair pyrimidine dimers (Yasui et al, 1994).…”

“…Phylogenetic analysis suggests that type I and type II CPD photolyases have a common ancestor but diverged early in evolution (Yasui et al, 1994). The two CPD photolyases encoded by the baculovirus ChchNPV share 45 % identity at the amino acid level and belong to class II (van Oers et al, 2005;Xu et al, 2008).…”

UV‐B component of sunlight causes measurable damage in field‐grown maize (Zea mays L.): developmental and cellular heterogeneity of damage and repair

“…The first type of repair is called 'light' repair or photoreactivation, and it generally occurs within a few hours. Specific photolyase enzymes require UV-A or blue light to energize direct reversal of either cyclobutane pyrimidine dimers (CPD) or 279 pyrimidine (6,4) pyrimidone dimers (6,4 photoproducts) created in DNA by UV-B exposure (Yasui et al 1994;Sancar 1996;Todo et al 1996). The second type of repair, called 'dark' or excision repair, involves removal of the damaged bases followed by synthesis of a repair patch.…”