Enrichment for histone H3 lysine 9 methylation at Alu repeats in human cells
Enrichment for histone H3 lysine 9 methylation at Alu repeats in human cells
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DOI：
10.1074/jbc.m304072200
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发表时间：
2003-07-25
影响因子：
4.8
通讯作者：
Issa, JPJ
中科院分区：
文献类型：
--
作者：
Kondo, Y;Issa, JPJ
本研究的目的是鉴定人类细胞中组蛋白H3赖氨酸9 （H3- lys(9)）甲基化的共同靶标，这种修饰通常与基因沉默相关。使用H3-Lys(9)甲基化抗体进行染色质免疫沉淀后，我们克隆了回收的DNA并对47个独立克隆进行了测序。其中38个（81%）克隆含有重复元件，包括短穿插转座元件（SINE或Alu元件）、长末端重复（LTR）、长穿插转座元件（LINE）或卫星区（ALR/Alpha） DNA，另外3个克隆位于Alu元件附近。对这些重复元件的进一步表征表明，32个（68%）克隆是Alu重复序列，对应于老年Alu亚家族（23个）和年轻Alu亚家族（9个）。使用保守的Alu引物，通过染色质免疫沉淀- pcr证实H3-Lys(9)甲基化的关联。此外，我们从恢复的克隆中随机选择5个Alu重复序列，并利用Alu元件侧面的引物集通过PCR确认与H3-Lys(9)的关联。DNA甲基转移酶抑制剂5-aza-2'-脱氧胞苷处理后，Alu元件中H3-Lys(9)甲基化水平迅速降低，提示H3-Lys(9)甲基化可能与通过DNA甲基化抑制Alu元件有关。因此，H3-Lys(9)甲基化富集于人类重复元件，特别是Alu元件，并可能在抑制这些元件的重组中发挥作用。
The aim of this study was to identify in human cells common targets of histone H3 lysine 9 (H3-Lys(9)) methylation, a modification that is generally associated with gene silencing. After chromatin immunoprecipitation using an H3-Lys(9) methylated antibody, we cloned the recovered DNA and sequenced 47 independent clones. Of these, 38 clones (81%) contained repetitive elements, either short interspersed transposable element (SINE or Alu elements), long terminal repeat (LTR), long interspersed transposable element (LINE), or satellite region (ALR/Alpha) DNA, and three additional clones were near Alu elements. Further characterization of these repetitive elements revealed that 32 clones (68%) were Alu repeats, corresponding to both old Alu (23 clones) and young Alu (9 clones) subfamilies. Association of H3-Lys(9) methylation was confirmed by chromatin immunoprecipitation-PCR using conserved Alu primers. In addition, we randomly selected 5 Alu repeats from the recovered clones and confirmed association with H3-Lys(9) by PCR using primer sets flanking the Alu elements. Treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine rapidly decreased the level of H3-Lys(9) methylation in the Alu elements, suggesting that H3-Lys(9) methylation may be related to the suppression of Alu elements through DNA methylation. Thus H3-Lys(9) methylation is enriched at human repetitive elements, particularly Alu elements, and may play a role in the suppression of recombination by these elements.