A putative blue-light receptor from Drosophila melanogaster

A gene encoding a 62.5 kDa homolog of Drosophila melanogaster photolyase wa s isolated. Purified recombinant protein contained a flavin adenine dinucle otide chromophore, The recombinant protein did not show photolyase activity for either cyclobutane pyrimidine dimers or 6-4 photoproducts in vitro as well as in vivo in Escherichia coil host cells, suggesting that the protein is not a DNA repair enzyme but a blue-light photoreceptor. Reverse transcr iption polymerase chain reaction analysis showed that the gene is more expr essed in head than in body and that it is more expressed in antennae than i n legs, wings and mouth appendages, In a phylogenetic tree of the photolyas e family, the Drosophila photolyase homolog is located in a cluster contain ing 6-4 photolyases and mammalian photolyase homologs, which is only distan tly related to the clade of higher plant blue-light photoreceptors, The mam malian photolyase homologs are more closely related to Drosophila 6-4 photo lyase than to the Drosophila photolyase homolog, suggesting different roles of the photolyase homologs.