Department of Biology, Duke University, Durham, NC, USA.
Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA.
Nat Plants. 2023 Aug;9(8):1291-1305. doi: 10.1038/s41477-023-01477-y. Epub 2023 Aug 3.
The DELLA genes, also known as 'Green Revolution' genes, encode conserved master growth regulators that control plant development in response to internal and environmental cues. Functioning as nuclear-localized transcription regulators, DELLAs modulate expression of target genes via direct protein-protein interaction of their carboxy-terminal GRAS domain with hundreds of transcription factors (TFs) and epigenetic regulators. However, the molecular mechanism of DELLA-mediated transcription reprogramming remains unclear. Here by characterizing new missense alleles of an Arabidopsis DELLA, repressor of ga1-3 (RGA), and co-immunoprecipitation assays, we show that RGA binds histone H2A via the PFYRE subdomain within its GRAS domain to form a TF-RGA-H2A complex at the target chromatin. Chromatin immunoprecipitation followed by sequencing analysis further shows that this activity is essential for RGA association with its target chromatin globally. Our results indicate that, although DELLAs are recruited to target promoters by binding to TFs via the LHR1 subdomain, DELLA-H2A interaction via the PFYRE subdomain is necessary to stabilize the TF-DELLA-H2A complex at the target chromatin. This study provides insights into the two distinct key modular functions in DELLA for its genome-wide transcription regulation in plants.
DELLA 基因，也被称为“绿色革命”基因，编码保守的主生长调节剂，可响应内部和环境线索控制植物发育。作为核定位转录调节剂，DELLA 通过其羧基末端 GRAS 结构域与数百种转录因子（TFs）和表观遗传调节剂的直接蛋白-蛋白相互作用来调节靶基因的表达。然而，DELLA 介导的转录重编程的分子机制尚不清楚。在这里，通过对拟南芥 DELLA 抑制子 repressor of ga1-3（RGA）的新错义等位基因进行表征和共免疫沉淀分析，我们表明 RGA 通过其 GRAS 结构域中的 PFYRE 亚结构域与组蛋白 H2A 结合，在靶染色质上形成 TF-RGA-H2A 复合物。染色质免疫沉淀结合测序分析进一步表明，这种活性对于 RGA 与全基因组靶染色质的关联是必需的。我们的结果表明，尽管 DELLA 通过 LHR1 亚结构域与 TFs 结合被招募到靶启动子，但通过 PFYRE 亚结构域的 DELLA-H2A 相互作用对于在靶染色质上稳定 TF-DELLA-H2A 复合物是必要的。这项研究为植物中 DELLA 对其全基因组转录调控的两种不同关键模块功能提供了深入了解。
