Class II photolyase in a microsporidian intracellular parasite.
Photoreactivation is the repair of DNA damage induced by ultraviolet light radiation using the energy contained in visible-light photons. The process is carried out by a single enzyme, photolyase, which is part of a large and ancient photolyase/cryptochrome gene family. We have characterised a photolyase gene from the microsporidian parasite, Antonospora locustae (formerly Nosema locustae) and show that it encodes a functional photoreactivating enzyme and is expressed in the infectious spore stage of the parasite's life cycle. Sequence and phylogenetic analyses show that it belongs to the class II subfamily of cyclobutane pyrimidine dimer repair enzymes. No photolyase is present in the complete genome sequence of the distantly related microsporidian, Encephalitozoon cuniculi, and this class of photolyase has never yet been described in fungi, the closest relatives of Microsporidia, raising questions about the evolutionary origin of this enzyme. This is the second environmental stress enzyme to be found in A.locustae but absent in E.cuniculi, and in the other case (catalase), the gene is derived by lateral transfer from a bacterium. It appears that A.locustae spores deal with environmental stress differently from E.cuniculi, these results lead to the prediction that they are more robust to environmental damage.
Slamovits
Claudio H
CH
Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.
Keeling
Patrick J
PJ
D000595:Amino Acid Sequence; D000818:Animals; D004249:DNA Damage; D004260:DNA Repair; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry*; D004307:Dose-Response Relationship, Radiation; D004926:Escherichia coli / Q000201:enzymology; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D005816:Genetic Complementation Test; D008027:Light; D016814:Microsporidia / Q000201:enzymology*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010641:Phenotype; D010802:Phylogeny; D011061:Poly A; D012313:RNA / Q000737:chemistry; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological
D011061:Poly A; D012313:RNA; D004255:Deoxyribodipyrimidine Photo-Lyase