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A UVB‐hypersensitive mutant in Arabidopsis thaliana is defective in the DNA damage response
Author(s) -
Sakamoto Ayako N.,
Lan Vo Thi Thuong,
Puripunyavanich Vichai,
Hase Yoshihiro,
Yokota Yuichiro,
Shikazono Naoya,
Nakagawa Mayu,
Narumi Issay,
Tanaka Atsushi
Publication year - 2009
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2009.03974.x
Subject(s) - biology , mutant , dna damage , arabidopsis , fusion protein , gene , microbiology and biotechnology , arabidopsis thaliana , dna , genetics , recombinant dna
Summary To investigate UVB DNA damage response in higher plants, we used a genetic screen to isolate Arabidopsis thaliana mutants that are hypersensitive to UVB irradiation, and isolated a UVB‐sensitive mutant, termed suv2 (for sensitive to UV 2) that also displayed hypersensitivity to γ‐radiation and hydroxyurea. This phenotype is reminiscent of the Arabidopsis DNA damage‐response mutant atr . The suv2 mutation was mapped to the bottom of chromosome 5, and contains an insertion in an unknown gene annotated as MRA19.1 . RT‐PCR analysis with specific primers to MRA19.1 detected a transcript consisting of 12 exons. The transcript is predicted to encode a 646 amino acid protein that contains a coiled‐coil domain and two instances of predicted PIKK target sequences within the N‐terminal region. Fusion proteins consisting of the predicted MRA19.1 and DNA‐binding or activation domain of yeast transcription factor GAL4 interacted with each other in a yeast two‐hybrid system, suggesting that the proteins form a homodimer. Expression of CYCB1;1:GUS gene, which encodes a labile cyclin:GUS fusion protein to monitor mitotic activity by GUS activity, was weaker in the suv2 plant after γ‐irradiation than in the wild‐type plants and was similar to that in the atr plants, suggesting that the suv2 mutant is defective in cell‐cycle arrest in response to DNA damage. Overall, these results suggest that the gene disrupted in the suv2 mutant encodes an Arabidopsis homologue of the ATR‐interacting protein ATRIP.