title: Induction and inhibition of cyclobutane pyrimidine dimer photolyase in etiolated cucumber (Cucumis sativus) cotyledons after ultraviolet irradiation depends on wavelength.
abstract: Under polychromatic ultraviolet (UV) irradiation (maximum energy at 327 nm) the activity of DNA photolyase specific to cyclobutane pyrimidine dimers (CPDs), CPD photolyase, increased by an amount which depended on UV irradiance, and the level of CPD photolyase gene (CsPHR) transcripts temporarily increased before the activity reached a constant level. UV light (>320 nm) was more effective than visible light at increasing CPD photolyase activity. In contrast, monochromatic UV irradiation at wavelengths <300 nm increased the level of CsPHR transcripts similarly to irradiation at wavelengths >320 nm, but reduced CPD photolyase activity compared with the dark control. Exposure of a CPD photolyase solution to UV-C (254 nm) reduced enzyme activity and induced accumulation of H(2)O(2). Addition of H(2)O(2) to the enzyme solution also inactivated CPD photolyase activity. These results suggest the possibility that reactive oxygen species participate in the inactivation of CPD photolyase in cotyledons exposed to UV irradiation of <300 nm.
authors.affiliation: Department of Bioscience and Technology, School of Engineering, Hokkaido Tokai University, Sapporo, Japan. takeuchi@db.htokai.ac.jp
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Taku
authors.initials: T
authors.lastname: Inoue
authors.forename: Kazuya
authors.initials: K
authors.lastname: Takemura
authors.forename: Megumi
authors.initials: M
authors.lastname: Hada
authors.forename: Shinya
authors.initials: S
authors.lastname: Takahashi
authors.forename: Motohide
authors.initials: M
authors.lastname: Ioki
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Nakajima
authors.forename: Noriaki
authors.initials: N
authors.lastname: Kondo
mesh_terms: D018548:Cotyledon / Q000201:enzymology* / Q000528:radiation effects; D018553:Cucumis sativus / Q000201:enzymology* / Q000528:radiation effects; D003624:Darkness; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D007700:Kinetics; D017785:Photons; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014466:Ultraviolet Rays
chemical_list: D010940:Plant Proteins; D004255:Deoxyribodipyrimidine Photo-Lyase; C522991:cyclobutane pyrimidine dimer photolyase, Cucumis sativus