Lämke Jörn, Brzezinka Krzysztof, Altmann Simone, Bäurle Isabel
Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany
EMBO J. 2016 Jan 18;35(2):162-75. doi: 10.15252/embj.201592593. Epub 2015 Dec 9.
In nature, plants often encounter chronic or recurring stressful conditions. Recent results indicate that plants can remember a past exposure to stress to be better prepared for a future stress incident. However, the molecular basis of this is poorly understood. Here, we report the involvement of chromatin modifications in the maintenance of acquired thermotolerance (heat stress [HS] memory). HS memory is associated with the accumulation of histone H3 lysine 4 di- and trimethylation at memory-related loci. This accumulation outlasts their transcriptional activity and marks them as recently transcriptionally active. High accumulation of H3K4 methylation is associated with hyper-induction of gene expression upon a recurring HS. This transcriptional memory and the sustained accumulation of H3K4 methylation depend on HSFA2, a transcription factor that is required for HS memory, but not initial heat responses. Interestingly, HSFA2 associates with memory-related loci transiently during the early stages following HS. In summary, we show that transcriptional memory after HS is associated with sustained H3K4 hyper-methylation and depends on a hit-and-run transcription factor, thus providing a molecular framework for HS memory.
在自然界中，植物常常会遭遇长期或反复出现的胁迫条件。最近的研究结果表明，植物能够记住过去所经历的胁迫，从而为未来的胁迫事件做好更充分的准备。然而，其分子机制却鲜为人知。在此，我们报道了染色质修饰在维持获得性耐热性（热胁迫[HS]记忆）中的作用。HS记忆与记忆相关位点处组蛋白H3赖氨酸4二甲基化和三甲基化的积累有关。这种积累在其转录活性消失后仍持续存在，并将这些位点标记为近期具有转录活性。H3K4甲基化的高积累与反复热胁迫后基因表达的超诱导有关。这种转录记忆以及H3K4甲基化的持续积累依赖于HSFA2，HSFA2是一种HS记忆所必需的转录因子，但不是初始热响应所必需的。有趣的是，HSFA2在热胁迫后的早期阶段短暂地与记忆相关位点结合。总之，我们表明热胁迫后的转录记忆与持续的H3K4高甲基化有关，并且依赖于一种“打了就跑”的转录因子，从而为HS记忆提供了一个分子框架。
