Tang Guangfei, Xia Haoxue, Huang Yufei, Guo Yuanwen, Chen Yun, Ma Zhonghua, Liu Wende
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
College of Plant Protection, Shenyang Agricultural University, Shenyang, 110866, China.
Genome Biol. 2024 Mar 11;25(1):67. doi: 10.1186/s13059-024-03209-7.
Bromo-adjacent homology-plant homeodomain domain containing protein 1 (BP1) is a reader of histone post-translational modifications in fungi. BP1 recognizes trimethylation of lysine 27 in histone H3 (H3K27me3), an epigenetic hallmark of gene silencing. However, whether and how BP1 participates in transcriptional repression remains poorly understood.
We report that BP1 forms phase-separated liquid condensates to modulate its biological function in Fusarium graminearum. Deletion assays reveal that intrinsically disordered region 2 (IDR2) of BP1 mediates its liquid-liquid phase separation. The phase separation of BP1 is indispensable for its interaction with suppressor of Zeste 12, a component of polycomb repressive complex 2. Furthermore, IDR2 deletion abolishes BP1-H3K27me3 binding and alleviates the transcriptional repression of secondary metabolism-related genes, especially deoxynivalenol mycotoxin biosynthesis genes.
BP1 maintains transcriptional repression by forming liquid-liquid phase-separated condensates, expanding our understanding of the relationship between post-translational modifications and liquid-liquid phase separation.
含溴相邻同源结构域-植物同源结构域蛋白1（BP1）是真菌中组蛋白翻译后修饰的识别蛋白。BP1识别组蛋白H3赖氨酸27的三甲基化（H3K27me3），这是基因沉默的一种表观遗传标志。然而，BP1是否以及如何参与转录抑制仍知之甚少。
我们报道BP1形成相分离的液体凝聚物以调节其在禾谷镰刀菌中的生物学功能。缺失分析表明BP1的内在无序区域2（IDR2）介导其液-液相分离。BP1的相分离对于其与多梳抑制复合物2的组分Zeste 12抑制因子的相互作用是必不可少的。此外，IDR2缺失消除了BP1-H3K27me3结合，并减轻了次生代谢相关基因，特别是脱氧雪腐镰刀菌烯醇霉菌毒素生物合成基因的转录抑制。
BP1通过形成液-液相分离的凝聚物维持转录抑制，扩展了我们对翻译后修饰与液-液相分离之间关系的理解。
