H3 lysine 9 methylation is maintained on a transcribed inverted repeat by combined action of SUVH6 and SUVH4 methyltransferases
H3 lysine 9 methylation is maintained on a transcribed inverted repeat by combined action of SUVH6 and SUVH4 methyltransferases
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DOI：
10.1128/mcb.25.23.10507-10515.2005
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发表时间：
2005-12-01
影响因子：
5.3
通讯作者：
Bender, J
中科院分区：
文献类型：
--
作者：
Ebbs, ML;Bartee, L;Bender, J
转录的反向重复序列通过产生双链RNA（dsRNA）是植物中RNA干扰和RNA指导的DNA甲基化的有效触发物。例如，拟南芥内源基因PAI 1-PAI 4的转录反向重复序列指导其自身以及两个未连接的重复派基因PAI 2和PAI 3的甲基化。在以前的工作中，我们发现SUVH 4/KYP组蛋白H3赖氨酸9（H3 K9）甲基转移酶的突变导致PAI 2和PAI 3上的DNA甲基化丢失，但不是在反向重复序列上。在这里，我们使用染色质免疫沉淀分析表明，转录的反向重复进行H3 K9甲基化，这是保持即使在suvh 4突变体。PAI 1-PAI 4 H3 K9甲基化和DNA甲基化也维持在suvh 6突变体中，该突变体与SUVH 4密切相关的基因有缺陷。然而，在suvh 4和suvh 6双突变体中，这两种表观遗传修饰在该位点都减少。相反，SUV H6在PAI 2、转座子序列或着丝粒重复序列上的H3 K9或DNA甲基化的维持中不起显著作用。因此，SUV H6优先在dsRNA源基因座处相对于RNA指导的染色质修饰的靶标具有活性。
Transcribed inverted repeats are potent triggers for RNA interference and RNA-directed DNA methylation in plants through the production of double-stranded RNA (dsRNA). For example, a transcribed inverted repeat of endogenous genes in Arabidopsis thaliana, PAI1-PAI4, guides methylation of itself as well as two unlinked duplicated PAI genes, PAI2 and PAI3. In previous work, we found that mutations in the SUVH4/KYP histone H3 lysine 9 (H3 K9) methyltransferase cause a loss of DNA methylation on PAI2 and PAI3, but not on the inverted repeat. Here we use chromatin immunoprecipitation analysis to show that the transcribed inverted repeat carries H3 K9 methylation, which is maintained even in an suvh4 mutant. PAI1-PAI4 H3 K9 methylation and DNA methylation are also maintained in an suvh6 mutant, which is defective for a gene closely related to SUVH4. However, both epigenetic modifications are reduced at this locus in an suvh4 suvh6 double mutant. In contrast, SUVH6 does not play a significant role in maintenance of H3 K9 or DNA methylation on PAI2, transposon sequences, or centromere repeat sequences. Thus, SUVH6 is preferentially active at a dsRNA source locus versus targets for RNA-directed chromatin modifications.