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Regulation of plant expression by DNA methylation

DNA 甲基化调控植物表达

基本信息

批准号：
01480016
负责人：
SANO Hiroshi
金额：
$ 4.22万
依托单位：
Akita Prefectural College of Agriculture
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01480016/
关键词：
DNA methylation dwarfism small GTP-binding protein ras-related gene Oryza sativa azacytidine rgp1 transgenic tobacco DNAメチル化 rasー関連遺伝子矮性植物 GTP結合蛋白質 rga1 矮性イネフザシチジン

项目摘要

Exposure of normal, tall rice (Oryza sativa) seedlings to 5-azacytidine, a powerful inhibitor of DNA methylation in vivo, induced both demethylation of genomic DNA and dwarf plants. Genes that had been affected by treatment were identified by differential screening of a DNA library, and a gene encoding a small GTP-binding protein, rgp1, was subsequently. The cDNA or rgp1 was found to encode a deduced protein of 226 amino acids (24.8kDa) with highest sequence similarity to the ras-related ypt3 protein of fission yeast. The rgp1 protein, rgp1-p25, expressed in transformed E.coli, clearly showed GTP-binding activity. To determine the physiological role of rgp1-p25, the coding region of rgp1 was introduced into tobacco plants in both sense and anti-sense orientations. Transformants, with rgp1 in either orientation, showed distinct phenotypic changes; reduced apical dominance, dwarfism and abnormal flower development. The expression of tgp1, a tobacco homologue of rgp1, was markedly reduced in anti-sense transformants, indicating that tha phenotypic changes may have been mediated by interference with tgp1, mRNA. In sense transformants, the changes may have been induced by over-production of rgp1-p25. We speculated that the increased tillering may be related to abnormal phytohormone metabolism or response pathways. A preliminaly experiment clearly showed that the content of zeation, one of the active cytokinins in higher plants, differed significantly between transformants and controls. Furthermore, transformants were found to respond differentially to externally-applied cytokinins. These observations indicate that the rgp1-p25 may be involved in either the regulation of cytokinin biosynthesis or, more probably, in its intracellular transport.

暴露于5-氮胞苷，一种强有力的抑制剂，在体内的DNA甲基化的正常，高大的水稻（Oryza sativa）幼苗，诱导基因组DNA的去甲基化和矮化植物。通过DNA文库的差异筛选鉴定了受治疗影响的基因，随后对编码小GTP结合蛋白rgp 1的基因进行了鉴定。该cDNA或rgp 1编码226个氨基酸（24.8kDa）的蛋白质，与裂殖酵母ras相关蛋白ypt 3的序列相似性最高。在转化的大肠杆菌中表达的rgp 1蛋白，rgp 1-p25，清楚地显示出GTP结合活性。为了确定rgp 1-p25的生理作用，将rgp 1的编码区以正义和反义方向导入烟草植株中。在任一方向上具有rgp 1的转化体表现出明显的表型变化：顶端优势降低、矮化和花发育异常。在反义转化体中，烟草同源基因tgp 1的表达显著降低，表明tgp 1的表达可能是通过干扰tgp 1 mRNA而介导的。在有义转化体中，这些变化可能是由rgp 1-p25的过量产生诱导的。我们推测，分蘖增加可能与植物激素代谢或响应途径异常有关。植物细胞分裂素Zeation的含量在转化体和对照之间有显著差异。此外，发现转化体对外部施加的细胞分裂素有差异反应。这些观察结果表明，rgp 1-p25可能参与细胞分裂素生物合成的调节，或更可能，在其细胞内运输。