An Arabidopsis photolyase mutant is hypersensitive to ultraviolet-B radiation.
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.
Landry
L G
LG
The Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY 14853-1801, USA.
Stapleton
A E
AE
Lim
J
J
Hoffman
P
P
Hays
J B
JB
Walbot
V
V
Last
R L
RL
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
D001051:Apoenzymes; D005656:Fungal Proteins; D008562:Membrane Glycoproteins; C091515:PHR1 protein, Candida albicans; D011740:Pyrimidine Dimers; D004255:Deoxyribodipyrimidine Photo-Lyase