National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, China.
Institute of Plant Science Paris-Saclay (IPS2), CNRS, INRAE, University Paris-Saclay, Orsay, France.
EMBO J. 2023 Nov 2;42(21):e114220. doi: 10.15252/embj.2023114220. Epub 2023 Sep 11.
DELLA proteins are master regulators of gibberellic acid (GA) signaling through their effects on gene expression. Enhanced DELLA accumulation in rice and wheat varieties has greatly contributed to grain yield increases during the green revolution. However, the molecular basis of DELLA-mediated gene repression remains elusive. In this work, we show that the rice DELLA protein SLENDER RICE1 (SLR1) forms a tripartite complex with Polycomb-repressive complex 2 (PRC2) and the histone deacetylase HDA702 to repress downstream genes by establishing a silent chromatin state. The slr1 mutation and GA signaling resulted in dissociation of PRC2 and HDA702 from GA-inducible genes. Loss-of-function or downregulation of the chromatin regulators impaired SLR1-dependent histone modification and gene repression. Time-resolved analysis of GA signaling revealed that GA-induced transcriptional activation was associated with a rapid increase of H3K9ac followed by H3K27me3 removal. Collectively, these results establish a general epigenetic mechanism for DELLA-mediated gene repression and reveal details of the chromatin dynamics during transcriptional activation stimulated by GA signaling.
DELLA 蛋白通过影响基因表达，成为赤霉素（GA）信号转导的主要调控因子。在绿色革命期间，水稻和小麦品种中 DELLA 积累的增强极大地促进了粮食产量的增加。然而，DELLA 介导的基因抑制的分子基础仍然难以捉摸。在这项工作中，我们表明，水稻 DELLA 蛋白 SLENDER RICE1（SLR1）与多梳抑制复合物 2（PRC2）和组蛋白去乙酰化酶 HDA702 形成三组分复合物，通过建立沉默的染色质状态来抑制下游基因。slr1 突变和 GA 信号导致 PRC2 和 HDA702 从 GA 诱导的基因中解离。染色质调控因子的功能丧失或下调损害了 SLR1 依赖的组蛋白修饰和基因抑制。GA 信号的时分辨析表明，GA 诱导的转录激活与 H3K9ac 的快速增加有关，随后是 H3K27me3 的去除。总的来说，这些结果为 DELLA 介导的基因抑制建立了一个普遍的表观遗传机制，并揭示了 GA 信号刺激转录激活过程中染色质动力学的细节。
