State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
Plant Cell Rep. 2018 Jan;37(1):115-123. doi: 10.1007/s00299-017-2207-z. Epub 2017 Sep 22.
The aleurone layer is crucial to seed germination. Using dissected aleurone layers, we found that GA increased histone acetylation accompanied by rDNA decondensation in aleurone layers during maize seed germination. Aleurone layers play an important role in cereal seed germination. In this study, we reported that rDNA chromatin was decondensed, accompanied with increased rDNA expression and genomic global hyperacetylation in gibberellin (GA)-treated maize-dissected aleurone layers. The activity analysis of histone acetyltransferase (HAT) and deacetylase (HDAC) showed that GA increased the level of histone acetylation by promoting the ratio of HAT/HDAC activity in aleurone layers. HDAC inhibitors TSA and CUDC-101 elevated the histone acetylation in aleurone layers accompanied by 45S rDNA decondensation. The further chromatin immunoprecipitation experiments showed that GA treatment promoted the level of histone acetylation in the promoter region of the rRNA and HAT/HDAC genes in aleurone layers. Taken together, these data indicated that histone acetylation mediates GA-regulated 45S rDNA chromatin decondensation in aleurone layers during maize seed germination.
糊粉层对于种子萌发至关重要。通过分离的糊粉层，我们发现 GA 可增加组蛋白乙酰化，伴随着 rDNA 解凝聚，从而促进玉米种子萌发过程中的糊粉层基因表达。糊粉层在谷类种子萌发中起着重要作用。在这项研究中，我们报道在 GA 处理的玉米糊粉层中 rDNA 染色质解凝聚，伴随着 rDNA 表达增加和基因组整体超乙酰化。组蛋白乙酰转移酶（HAT）和去乙酰化酶（HDAC）的活性分析表明，GA 通过促进糊粉层中 HAT/HDAC 活性的比值来增加组蛋白乙酰化水平。HDAC 抑制剂 TSA 和 CUDC-101 提高了糊粉层中的组蛋白乙酰化水平，伴随着 45S rDNA 解凝聚。进一步的染色质免疫沉淀实验表明，GA 处理促进了糊粉层中 rRNA 和 HAT/HDAC 基因启动子区域的组蛋白乙酰化水平。总之，这些数据表明，组蛋白乙酰化介导了 GA 调控的玉米种子萌发过程中糊粉层中 45S rDNA 染色质的解凝聚。
