The conserved splicing factor PRP21 regulates abscisic acid response and seed germination in Arabidopsis [ChIP-seq]

Seed germination is a critical developmental stage in the life cycle of plants, and its regulation is essential for ensuring crop productivity, particularly under adverse environmental conditions. Here, we find that the Arabidopsis thaliana PRE-MRNA-PROCESSING (PRP21) is crucial for the regulation of abscisic acid (ABA) response of seed germination. Our RNA deep sequencing and poly(A) tag sequencing analyses reveal that PRP21 is involved in pre-mRNA splicing, genome-wide gene transcription, and mRNA 3' end processing, highlighting its multifunctional role in gene regulation. Furthermore, we find that PRP21 interacts with various splicing factors and small nuclear ribonucleoproteins, suggesting its involvement in spliceosome assembly. Additionally, we demonstrate that PRP21 negatively regulates the expression of ABA-responsive genes, such as ABSCISIC ACID-INSENSITIVE 3 (ABI3), ABSCISIC ACID-INSENSITIVE 5 (ABI5), EARLY METHIONINE-LABELED 1 (EM1), and EARLY METHIONINE-LABELED 6 (EM6), thereby modulating ABA response and seed germination. Our findings underscore the importance of PRP21 in coordinating transcriptional and post-transcriptional processes, and provide insights into the molecular mechanisms underlying seed germination, potentially guiding crop improvement for stress tolerance. Overall design: Examination of Pol II level in wild type, prp21 mutant.

种子萌发是植物生命周期中的关键发育阶段，其调控对于保障作物产量至关重要，在逆境环境下尤为如此。本研究发现，拟南芥（Arabidopsis thaliana）的前体mRNA加工因子PRP21（PRE-MRNA-PROCESSING）在调控种子萌发的脱落酸（abscisic acid, ABA）响应过程中发挥关键作用。本研究通过RNA深度测序（RNA deep sequencing）及poly(A)标签测序（poly(A) tag sequencing）分析发现，PRP21参与前体mRNA剪接（pre-mRNA splicing）、全基因组基因转录及mRNA 3'端加工过程，凸显其在基因调控中的多功能性。此外，本研究发现PRP21可与多种剪接因子及小核核糖核蛋白（small nuclear ribonucleoproteins）相互作用，表明其参与剪接体（spliceosome）的组装过程。另外，本研究证实PRP21对脱落酸响应基因的表达具有负调控作用，包括脱落酸不敏感3（ABSCISIC ACID-INSENSITIVE 3, ABI3）、脱落酸不敏感5（ABSCISIC ACID-INSENSITIVE 5, ABI5）、蛋氨酸早期标记1（EARLY METHIONINE-LABELED 1, EM1）及蛋氨酸早期标记6（EARLY METHIONINE-LABELED 6, EM6），从而调控ABA响应及种子萌发过程。本研究结果凸显了PRP21在协调转录与转录后调控过程中的重要作用，为解析种子萌发的分子机制提供了新的理论视角，有望为作物抗逆遗传改良提供指导方向。实验设计：检测野生型与prp21突变体中RNA聚合酶II（Pol II）的水平。