Cytosine methylation is associated with RNA silencing in silenced plants but not with systemic and transitive RNA silencing through grafting
Cytosine methylation is associated with RNA silencing in silenced plants but not with systemic and transitive RNA silencing through grafting
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DOI：
10.1016/j.gene.2007.04.003
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发表时间：
2007-07-15
期刊：
影响因子：
3.5
通讯作者：
Nishiguchi, Masamichi
中科院分区：
文献类型：
--
作者：
Haque, A. K. M. Namul;Yamaoka, Naoto;Nishiguchi, Masamichi
RNA沉默通常与靶基因的甲基化有关。在携带甘薯羽状斑驳病毒外壳蛋白基因的 5' 区域（200 或 400 bp）或整个区域（CP，包括 3' 非翻译区域）的转录后沉默或非沉默烟草中研究了转基因的 DNA 甲基化水平。在沉默株系的对称（CpG、CpNpG）和非对称（CpHpH）环境（CpG > CpNpG > CpHpH）中观察到较高水平的转基因胞嘧啶甲基化，但在非沉默株系中转基因胞嘧啶甲基化水平非常低或没有转基因甲基化。在来自沉默砧木的非沉默接穗中诱导RNA沉默并扩散至转基因mRNA的3'区域(Haque等人，Plant Mol.Biol.2007；63：35-47)。在该系统中，在嫁接到沉默或非沉默砧木上后的不同时间间隔分析接穗中的转基因甲基化水平，以研究转基因甲基化是否与RNA沉默的诱导或传递性相关。我们观察到，在接穗的初始靶标或延伸区域中转基因甲基化水平没有变化。这些结果表明，转基因甲基化与个体转化体中的RNA沉默相关，但与系统性RNA沉默和/或通过嫁接传递的RNA沉默无关。 (C) 2007 年由 Elsevier B.V. 出版
RNA silencing is often associated with methylation of the target gene. The DNA methylation level of transgenes was investigated in posttranscriptionally silenced or non-silenced Nicotiana benthamiana carrying either the 5' region (200 or 400 bp) or the entire region of the coat protein gene (CP, including the 3' non-translated region) of Sweet potato feathery mottle virus. Higher levels of transgene cytosine methylation were observed in both symmetrical (CpG, CpNpG) and non-symmetrical (CpHpH) contexts (CpG > CpNpG > CpHpH) in silenced lines, but there was very lower levels or no transgene methylation in non-silenced lines. RNA silencing was induced in non-silenced scions from silenced rootstocks and spread to the 3' region of the transgene mRNA (Haque et al, Plant Mol. Biol. 2007; 63: 35-47). In this system, transgene methylation levels were analyzed in scions at different time intervals after being grafted onto silenced or non-silenced rootstocks to investigate if transgene methylation was associated with induction or transitivity of RNA silencing. We observed that, there was no change of transgene methylation level in the initial target or in extended regions in scions. These results showed that transgene methylation was associated with RNA silencing in individual transformants, but it was not associated with systemic RNA silencing and/or transitive RNA silencing through grafting. (C) 2007 Published by Elsevier B.V.