An Arabidopsis photolyase mutant is hypersensitive to ultraviolet-B radiation

Proc Natl Acad Sci U S A. 1997 Jan 7;94(1):328-32. doi: 10.1073/pnas.94.1.328.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Apoenzymes / genetics*
  • Arabidopsis / enzymology
  • Arabidopsis / genetics
  • Arabidopsis / radiation effects*
  • DNA Repair / genetics*
  • Deoxyribodipyrimidine Photo-Lyase / genetics*
  • Dose-Response Relationship, Radiation
  • Fungal Proteins*
  • Membrane Glycoproteins*
  • Mutagenesis
  • Mutation*
  • Pyrimidine Dimers / metabolism
  • Radiation Tolerance / genetics*
  • Ultraviolet Rays / adverse effects


  • Apoenzymes
  • Fungal Proteins
  • Membrane Glycoproteins
  • PHR1 protein, Candida albicans
  • Pyrimidine Dimers
  • Deoxyribodipyrimidine Photo-Lyase