title: Linear DNA intermediates of the Tto1 retrotransposon in Gag particles accumulated in stressed tobacco and Arabidopsis thaliana.
abstract: The active transcription of some plant retrotransposons under diverse stress conditions suggests active transposition. However, transposition has been demonstrated only during tissue/cell culture. To examine whether transposition is activated under conditions other than tissue/cell culture, DNA intermediates for retrotransposition of the tobacco retrotransposon Tto1 were analysed. Using transgenic Arabidopsis callus expressing high levels of Tto1 RNA in a ddm1 hypomethylation mutant background, the existence of extrachromosomal Tto1 linear DNA molecules in a Gag-particle fraction was demonstrated. By combination with ligation-mediated PCR amplification, we detected Tto1 linear DNA molecules in particle fractions from callus and methyl jasmonate-treated leaves of tobacco, but not from non-stressed leaves. Tto1 DNA intermediates could not be detected in the tobacco corolla where Tto1 is expressed. These results indicate that the transcriptional activation of Tto1 by defence-related stresses leads to the synthesis of DNA intermediates, whereas post-transcriptional suppression of Tto1 activity is suggested in the corolla.
authors.affiliation: Molecular Genetics Department, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Takeda
authors.forename: K
authors.initials: K
authors.lastname: Sugimoto
authors.forename: T
authors.initials: T
authors.lastname: Kakutani
authors.forename: H
authors.initials: H
authors.lastname: Hirochika
mesh_terms: D000941:Antigens / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics*; D018744:DNA, Plant / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D018749:RNA, Plant / Q000096:biosynthesis; D018626:Retroelements / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics*
chemical_list: D000941:Antigens; D018744:DNA, Plant; D018749:RNA, Plant; D018626:Retroelements