| Co-Investigator(Kenkyū-buntansha) |
SAKAMOTO Wataru Res. Inst. for Biores., Okayama University, Associate Professor, 資源生物科学研究所, 助教授 (20222002)
MASUDA Masaharu Fac. Agr., Okayama University, Professor, 農学部, 教授 (90026617)
OGURA Yutaka Res. Inst. for Biores., Okayama University, Assistant Professor, 資源生物科学研究所, 助手 (60224193)
OKUMOTO Yutaka Grad. Sch. Agr., Kyoto Univ., Associate Professor, 大学院・農学研究科, 助教授 (90152438)
HASEGAWA Hiroshi Sch. Env. Sci., Univ. Shiga Pref., Professor, 環境科学部, 教授 (00090457)
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| Research Abstract |
For isolating a new transposon in higher plants, the selection of mutants resistant to hydroxyproline (a proline analog) was conducted, because some mutants resistant to an amino acid analog have been controlled by curious genetic behavior. However, through the study no evidence for transposable elements was obtained. (Hasegawa).
Unlike most other cut-and-paste type transposons, the transposition frequency of Tam3 in Antirrhinum is tightly controlled by temperature : Tam3 transposes rarely at 25 ℃, but much more frequently at 15 ℃. We found that temperature shift induced a remarkable change of the methylation state of the Tam3 end regions : higher temperature resulted in hyper-methylation, while lower temperature resulted in reduced methylation (kishima).
We carried out PCR with primers specific to the TIRs of a 1.3-kb transposon-like element Lyt1 from tomato to search for new members of the Lyt family. Among the amplified products, one fragment had a 2.7-kb insertion in a sequence corre
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sponding to Lyt1 and the putative Lyt element containing this sequence was termed Lyt2. The copy number of Lyt2-related sequences in the tomato genome was estimated to be approximately 20 by Southern blot analysis (Ogura and Masuda).
The mutable slender glume gene (slg), a recessive mutant gene induced from rice variety Gimbozu, was assumed to be controlled by a newly found transposon (named Sairyu, meaning slender glume in Japanese) belongs to MITEs family in rice, we suggest that slg is inactivated Rurm1 due to the insertion of Sairyu and that reverse mutation of slg is ascribed to the reactivation of Rurm1 caused by the deletion of Sairyu (Okumoto).
An Arabidopsis variegated mutant was isolated by T-DNA tagging. Cloning and molecular characterization of the VAR2 locus revealed that it potentially encodes a chloroplastic homologue of FtsH, an ATP-dependent metalloprotease that belongs to a large protein family involved in various cellular functions (Sakamoto). A mutable chlorophyll mutant was induced from stable chlorophyll mutants by carbon ion beam irradiation. This mutability of the induced mutant was inherited, suggesting that cryptic silent transposon might be reactivated by ion beam irradiation (Maekawa and Tanaka). Less
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