A methyltransferase required for proper timing of the vernalization response in Arabidopsis
A methyltransferase required for proper timing of the vernalization response in Arabidopsis
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DOI：
10.1073/pnas.1423585112
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发表时间：
2015-02-17
影响因子：
11.1
通讯作者：
Amasino, Richard M.
中科院分区：
文献类型：
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作者：
Lee, Joohyun;Yun, Jae-Young;Amasino, Richard M.
长时间暴露在冬季寒冷的环境中，使许多植物物种能够通过一个称为春化的过程开花。在拟南芥中，春化作用是通过多梳抑制复合物2（PRC2）介导的FLC染色质上表观遗传沉默标记H3K27me3密度的增加，由花抑制基因FLOWERYLOCUS C（FLC）的表观遗传沉默引起的。在冷暴露期间，诱导编码独特的冷特异性PRC2组分的基因，即春化不敏感3（VIN 3），其是PRC2介导的FLC沉默所必需的。在这里，我们表明SET DOMAIN GROUP 7（SDG 7）是VIN 3诱导和春化过程的适当时机所必需的。SDG7的缺失导致春化超敏表型，以及更快速的低温介导的VIN 3上调。在没有寒冷的情况下，SDG7的丢失导致长非编码RNA水平升高，这些RNA被认为参与FLC的表观遗传抑制。此外，SDG 7的损失导致在不存在冷暴露的情况下FLC染色质上的H3K27me3沉积增加，并且在冷处理期间H3K27me3扩散增强。因此，SDG7是春化作用的负调节因子，并且SDG7的损失产生了没有冷暴露的部分春化状态。
Prolonged exposure to winter cold enables flowering in many plant species through a process called vernalization. In Arabidopsis, vernalization results from the epigenetic silencing of the floral repressor FLOWERING LOCUS C (FLC) via a Polycomb Repressive Complex 2 (PRC2)-mediated increase in the density of the epigenetic silencing mark H3K27me3 at FLC chromatin. During cold exposure, a gene encoding a unique, cold-specific PRC2 component, VERNALIZATION INSENSITIVE 3 (VIN3), which is necessary for PRC2-mediated silencing of FLC, is induced. Here we show that SET DOMAIN GROUP 7 (SDG7) is required for proper timing of VIN3 induction and of the vernalization process. Loss of SDG7 results in a vernalization-hypersensitive phenotype, as well as more rapid cold-mediated up-regulation of VIN3. In the absence of cold, loss of SDG7 results in elevated levels of long noncoding RNAs, which are thought to participate in epigenetic repression of FLC. Furthermore, loss of SDG7 results in increased H3K27me3 deposition on FLC chromatin in the absence of cold exposure and enhanced H3K27me3 spreading during cold treatment. Thus, SDG7 is a negative regulator of vernalization, and loss of SDG7 creates a partially vernalized state without cold exposure.