Müller Andreas, Marins Mozart, Kamisugi Yasuko, Meyer Peter
Leeds Institute for Plant Biotechnology and Agriculture (LIBA), Centre for Plant Science, University of Leeds, UK.
Plant Mol Biol. 2002 Mar;48(4):383-99. doi: 10.1023/a:1014091131490.
A repetitive DNA sequence (RPS) from Petunia hybrida had previously been shown to enhance expression variegation in petunia and tobacco and to carry a hot spot for de novo DNA methylation. Here we show that a strong de novo hypermethylation site is located within a palindromic segment of the RPS and present indirect evidence, based on sequence homologies to other repeat units within the RPS, for the formation of secondary structures at the methylation site in vivo. We demonstrate that the palindromic RPS element, which is moderately to highly repetitive in petunia, does not predominantly localise to constitutive heterochromatin. To test whether the RPS is subject to de novo methylation due to its repetitive nature or to intrinsic signals within the RPS, we integrated the RPS into the genome of Arabidopsis thaliana, a plant lacking homology to the RPS. Our data indicate that the palindromic element also acts as a de novo hypermethylation site in the non-repetitive genomic background of Arabidopsis, strongly suggesting a signal function of the palindromic RPS element.
矮牵牛中的一个重复DNA序列（RPS）此前已被证明可增强矮牵牛和烟草中的表达变异，并带有一个从头DNA甲基化热点。在此我们表明，一个强烈的从头超甲基化位点位于RPS的一个回文片段内，并基于与RPS内其他重复单元的序列同源性，提供了体内甲基化位点形成二级结构的间接证据。我们证明，在矮牵牛中中度至高度重复的回文RPS元件并不主要定位于组成型异染色质。为了测试RPS是因其重复性质还是RPS内的内在信号而发生从头甲基化，我们将RPS整合到拟南芥的基因组中，拟南芥是一种与RPS缺乏同源性的植物。我们的数据表明，该回文元件在拟南芥的非重复基因组背景中也作为一个从头超甲基化位点，强烈暗示了回文RPS元件的信号功能。
