State Key Laboratory of Plant Genomics, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Plant Cell. 2019 Sep;31(9):2187-2205. doi: 10.1105/tpc.19.00115. Epub 2019 Jul 18.
Groucho/Thymidine uptake 1 (Gro/Tup1) family proteins are evolutionarily conserved transcriptional coregulators in eukaryotic cells. Despite their prominent function in transcriptional repression, little is known about their role in transcriptional activation and the underlying mechanism. Here, we report that the plant Gro/Tup1 family protein LEUNIG_HOMOLOG (LUH) activates MYELOCYTOMATOSIS2 (MYC2)-directed transcription of and via the Mediator complex coactivator and the histone acetyltransferase HAC1. We show that the Mediator subunit MED25 physically recruits LUH to MYC2 target promoters that then links MYC2 with HAC1-dependent acetylation of Lys-9 of histone H3 (H3K9ac) to activate and Moreover, LUH promotes hormone-dependent enhancement of protein interactions between MYC2 and its coactivators MED25 and HAC1. Our results demonstrate that LUH interacts with MED25 and HAC1 through its distinct domains, thus imposing a selective advantage by acting as a scaffold for MYC2 activation. Therefore, the function of LUH in regulating jasmonate signaling is distinct from the function of TOPLESS, another member of the Gro/Tup1 family that represses MYC2-dependent gene expression in the resting stage.
Groucho/胸苷摄取 1（Gro/Tup1）家族蛋白是真核细胞中进化上保守的转录共调节因子。尽管它们在转录抑制中具有突出的功能，但对其在转录激活中的作用及其潜在机制知之甚少。在这里，我们报告植物 Gro/Tup1 家族蛋白 LEUNIG_HOMOLOG（LUH）通过中介复合物共激活因子和组蛋白乙酰转移酶 HAC1 激活 MYELOCYTOMATOSIS2（MYC2）指导的 和 的转录。我们表明，中介亚基 MED25 物理募集 LUH 到 MYC2 靶启动子，然后将 MYC2 与 HAC1 依赖性赖氨酸 9 的组蛋白 H3 乙酰化（H3K9ac）联系起来，以激活 和 。此外，LUH 促进激素依赖性增强 MYC2 与其共激活因子 MED25 和 HAC1 之间的蛋白质相互作用。我们的结果表明，LUH 通过其独特的结构域与 MED25 和 HAC1 相互作用，从而通过充当 MYC2 激活的支架来发挥选择性优势。因此，LUH 在调节茉莉酸信号中的功能与 Gro/Tup1 家族的另一个成员 TOPLESS 不同，后者在静止阶段抑制 MYC2 依赖的基因表达。
