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gene promotes progression of endo-reduplication and confers increased tolerance towards ultraviolet B lightHase, Yoshihiro; Trung, K. H.*; Matsunaga, Tsukasa*; Tanaka, Atsushi
Plant Journal, 46(2), p.317 - 326, 2006/04
Times Cited Count：102 Percentile：89.53(Plant Sciences)We have isolated and characterized a new ultraviolet-B (UV-B)-resistant mutant, , of Arabidopsis. The fresh weight of plants grown under supplemental UV-B light was more than twice that of the wild type. No significant difference was found in the ability to repair the UV-B-induced cyclobutane pyrimidine dimers (CPDs), or in the amount of UV-B absorptive compounds, both of which are well known factors that contribute to UV sensitivity. Positional cloning revealed that the 
gene encodes a novel basic protein of unknown function. We found that the hypocotyl cells in undergo one extra round of endoreduplication. The mutation also promoted the progression of endoreduplication during leaf development. The gene is expressed mainly in actively dividing cells. In the leaves of P::GUS plants, the GUS signal disappeared in basipetal fashion as the leaf developed. The total leaf blade area was not different between and the wild type through leaf development, while the average cell area in the adaxial epidermis was considerably larger in , suggesting that the leaves have fewer but larger epidermal cells. These results suggest that the is necessary for the maintenance of the mitotic state and the loss of function stimulated endoreduplication. Tetraploid Arabidopsis was hyperresistant to UV-B compared to diploid Arabidopsis, suggesting that the enhanced polyploidization is responsible for the increased UV-B tolerance of the .
, 
or 
gene product for UV resistance in 
Tanaka, Masashi*; Narumi, Issei; Funayama, Tomoo; Kikuchi, Masahiro; Watanabe, Hiroshi*; Matsunaga, Tsukasa*; Nikaido, Osamu*; Yamamoto, Kazuo*
Journal of Bacteriology, 187(11), p.3693 - 3697, 2005/06
Times Cited Count：47 Percentile：62.27(Microbiology)no abstracts in English
gene causes hypersensitivity to Ultraviolet B light and 
-rays in Arabidopsis; Implication of the presence of a translesion synthesis mechanism in plantsSakamoto, Ayako; Lan, V. T. T.; Hase, Yoshihiro; Shikazono, Naoya; Matsunaga, Tsukasa*; Tanaka, Atsushi
Plant Cell, 15(9), p.2042 - 2057, 2003/09
Times Cited Count：81 Percentile：84.23(Biochemistry & Molecular Biology)In order to investigate UV-response mechanisms in higher plants, we isolated a UV-sensitive mutant, 
, in 
. The root growth of was inhibited after UV-B irradiation under both photoreactivating and non-photoreactivating conditions. We found that chromosome 1 of was broken at least at three points, causing chromosome inversion and translocation. A gene disrupted by this rearrangement encoded the catalytic subunit of DNA polymerase 
(), which is thought to be involved in translesion synthesis. The seedlings were also sensitive to -rays and MMC, which are known to inhibit DNA replication. The incorporation of BrdU after UV-B irradiation was less in 
than in the wild type plant. These results suggest that UV-damaged DNA interrupted DNA replication in the mutant, leading to the inhibition of cell division and root elongation.
mutantKiyosawa, Kazuhiro*; Tanaka, Masashi*; Matsunaga, Tsukasa*; Nikaido, Osamu*; Yamamoto, Kazuo
Mutation Research; DNA Repair, 487(3-4), p.149 - 156, 2001/12
no abstracts in English
gene, which promotes the progression of endoreduplication, confers an increased tolerance against UV-B lightHase, Yoshihiro; Trung, K. H.*; Matsunaga, Tsukasa*; Tanaka, Atsushi
no journal, ,
We have isolated and characterized an ultraviolet-B resistant mutant, uvi4, of Arabidopsis. The fresh weight of uvi4 plants grown under supplemental UV-B light was more than twice of that of the wild type. No significant difference was found in the ability to repair the UV-B-induced cyclobutane pyrimidine dimmers or in the amount of UV-B absorptive compounds, both of which are well known factors that contribute to UV sensitivity. Positional cloning revealed that the UVI4 gene encodes a novel basic protein of unknown function. The UVI4 gene is expressed mainly in actively dividing cells. We found that the hypocotyls cells in uvi4 undergo one extra round of endoreduplication. The uvi4 mutation also promoted the progression of endoreduplication during leaf development. Tetraploid Arabidopsis was hyperresistant to UV-B than diploid Arabidopsis. These results suggest that the enhanced polyploidization is responsible for the increased UV-B tolerance of the uvi4.
