Identification of genes preventing transgenerational transmission of stress-induced epigenetic states
Identification of genes preventing transgenerational transmission of stress-induced epigenetic states
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DOI：
10.1073/pnas.1402275111
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发表时间：
2014-06-10
影响因子：
11.1
通讯作者：
Paszkowski, Jerzy
中科院分区：
文献类型：
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作者：
Iwasaki, Mayumi;Paszkowski, Jerzy
环境诱导的表观遗传性状跨代传播的例子仍然很少且存在争议。非生物胁迫可以释放表观遗传抑制的转座子的转录，值得注意的是，这种激活只是暂时的。因此，对抗应激触发的染色质变化的有丝分裂和减数分裂遗传的机制可能一定存在，但尚未明确。为了揭示这些机制，我们筛选了在重置应激诱导的表观遗传沉默缺失方面受损的拟南芥突变体，发现两个染色质调节因子，DNA甲基化减少1（DDM1）和Morpheus' Molecule1（MOM1），冗余地恢复应激前状态，从而消除“表观遗传应激记忆”。在 ddm1 突变体中，应激会过度激活异染色质转录，并且转录持续时间比野生型更长。然而，这种新获得的状态不会传递给后代。引人注目的是，尽管在 mom1 突变体中胁迫诱导的转录与野生型一样迅速沉默，但在 ddm1 mom1 双突变体中，胁迫的转录特征能够持续存在，并在小苗时受到胁迫的植物后代中发现。我们的结果揭示了 DDM1 和 MOM1 在快速重置应激诱导的表观遗传状态方面的一个重要的、以前未被识别的功能，因此也可以防止它们的有丝分裂传播和跨代遗传。
Examples of transgenerational transmission of environmentally induced epigenetic traits remain rare and disputed. Abiotic stress can release the transcription of epigenetically suppressed transposons and, noticeably, this activation is only transient. Therefore, it is likely that mechanisms countering the mitotic and meiotic inheritance of stress-triggered chromatin changes must exist but are undefined. To reveal these mechanisms, we screened for Arabidopsis mutants impaired in the resetting of stress-induced loss of epigenetic silencing and found that two chromatin regulators, Decrease in DNA methylation1 (DDM1) and Morpheus' Molecule1 (MOM1), act redundantly to restore prestress state and thus erase "epigenetic stress memory". In ddm1 mutants, stress hyperactivates heterochromatic transcription and transcription persists longer than in the wild type. However, this newly acquired state is not transmitted to the progeny. Strikingly, although stress-induced transcription in mom1 mutants is as rapidly silenced as in wild type, in ddm1 mom1 double mutants, transcriptional signatures of stress are able to persist and are found in the progeny of plants stressed as small seedlings. Our results reveal an important, previously unidentified function of DDM1 and MOM1 in rapid resetting of stress induced epigenetic states, and therefore also in preventing their mitotic propagation and transgenerational inheritance.