Cloning and characterization of a gene (UVR3) required for photorepair of 6-4 photoproducts in Arabidopsis thaliana.
UV radiation induces two major classes of pyrimidine dimers: the pyrimidine [6-4] pyrimidone photoproduct (6-4 product) and the cyclobutane pyrimidine dimer (CPD). Many organisms produce enzymes, termed photolyases, that specifically bind to these damage products and split them via a UV-A/blue light-dependent mechanism, thereby reversing the damage. These photolyases are specific for either CPDs or 6-4 products. A gene that expresses a protein with 6-4 photolyase activity in vitro was recently cloned from Drosophila melanogaster and Xenopus laevis. We report here the isolation of a homolog of this gene, cloned on the basis of sequence similarity, from the higher plant Arabidopsis thaliana. This cloned gene produces a protein with 6-4 photolyase activity when expressed in Escherichia coli. We also find that a previously described mutant of Arabidopsis (uvr3) that is defective in photoreactivation of 6-4 products carries a nonsense mutation in this 6-4 photolyase homolog. We have therefore termed this gene UVR3. Although homologs of this gene have previously been shown to produce a functional 6-4 photolyase when expressed in heterologous systems, this is the first demonstration of a requirement for this gene for photoreactivation of 6-4 products in vivo.
Nakajima
S
S
Biological Institute, Graduate School of Science, Tohoku University, Sendai 980-77, Japan.
Sugiyama
M
M
Iwai
S
S
Hitomi
K
K
Otoshi
E
E
Kim
S T
ST
Jiang
C Z
CZ
Todo
T
T
Britt
A B
AB
Yamamoto
K
K
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D019755:Carbon-Carbon Lyases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004260:DNA Repair; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D008969:Molecular Sequence Data; D009154:Mutation; D010777:Photochemistry; D010802:Phylogeny; D011740:Pyrimidine Dimers / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D013053:Spectrophotometry; D014466:Ultraviolet Rays
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D011740:Pyrimidine Dimers; D011993:Recombinant Fusion Proteins; C058406:pyrimidine-pyrimidone dimer; D019755:Carbon-Carbon Lyases; C110458:UVR3 protein, Arabidopsis