title: An Arabidopsis photolyase mutant is hypersensitive to ultraviolet-B radiation.
abstract: Photolyases are DNA repair enzymes that use energy from blue light to repair pyrimidine dimers. We report the isolation of an Arabidopsis thaliana mutant (uvr2-1) that is defective in photorepair of cyclobutylpyrimidine dimers (CPDs). Whereas uvr2-1 is indistinguishable from wild type in the absence of UV light, low UV-B levels inhibit growth and cause leaf necrosis. uvr2-1 is more sensitive to UV-B than wild type when placed under white light after UV-B treatment. In contrast, recovery in darkness or in light lacking photoreactivating blue light results in equal injury in uvr2-1 and wild type. The uvr2-1 mutant is unable to remove CPDs in vivo, and plant extracts lack detectable photolyase activity. This recessive mutation segregates as a single gene located near the top of chromosome 1, and is a structural gene mutation in the type II CPD photolyase PHR1. This mutant provides evidence that CPD photolyase is required for plant survival in the presence of UV-B light.
authors.affiliation: The Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY 14853-1801, USA.
authors.forename: L G
authors.initials: LG
authors.lastname: Landry
authors.forename: A E
authors.initials: AE
authors.lastname: Stapleton
authors.forename: J
authors.initials: J
authors.lastname: Lim
authors.forename: P
authors.initials: P
authors.lastname: Hoffman
authors.forename: J B
authors.initials: JB
authors.lastname: Hays
authors.forename: V
authors.initials: V
authors.lastname: Walbot
authors.forename: R L
authors.initials: RL
authors.lastname: Last
mesh_terms: D001051:Apoenzymes / Q000235:genetics*; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects*; D004260:DNA Repair / Q000235:genetics*; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000235:genetics*; D004307:Dose-Response Relationship, Radiation; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; D016296:Mutagenesis; D009154:Mutation; D011740:Pyrimidine Dimers / Q000378:metabolism; D011836:Radiation Tolerance / Q000235:genetics*; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D001051:Apoenzymes; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; C091515:PHR1 protein, Candida albicans; D011740:Pyrimidine Dimers; D004255:Deoxyribodipyrimidine Photo-Lyase