Institute of Plant and Microbial biology, Academia Sinica, Taipei, Taiwan.
Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei, Taiwan.
Plant Physiol. 2021 Apr 2;185(3):1229-1241. doi: 10.1093/plphys/kiaa103.
Plants perceive dynamic light conditions and optimize their growth and development accordingly by regulating gene expression at multiple levels. Alternative splicing (AS), a widespread mechanism in eukaryotes that post-transcriptionally generates two or more messenger RNAs (mRNAs) from the same pre-mRNA, is rapidly controlled by light. However, a detailed mechanism of light-regulated AS is still not clear. In this study, we demonstrate that histone 3 lysine 36 trimethylation (H3K36me3) rapidly and differentially responds to light at specific gene loci with light-regulated intron retention (IR) of their transcripts in the moss Physcomitrella patens. However, the level of H3K36me3 following exposure to light is inversely related to that of IR events. Physcomitrella patens MORF-related gene 1 (PpMRG1), a chromatin adaptor, bound with higher affinity to H3K36me3 in light conditions than in darkness and was differentially targeted to gene loci showing light-responsive IR. Transcriptome analysis indicated that PpMRG1 functions in the regulation of light-mediated AS. Furthermore, PpMRG1 was also involved in red light-mediated phototropic responses. Our results suggest that light regulates histone methylation, which leads to alterations of AS patterns. The chromatin adaptor PpMRG1 potentially participates in light-mediated AS, revealing that chromatin-coupled regulation of pre-mRNA splicing is an important aspect of the plant's response to environmental changes.
植物通过在多个水平上调节基因表达来感知动态光照条件，并相应地优化其生长和发育。可变剪接（AS）是真核生物中一种广泛存在的机制，它通过转录后从同一前体 mRNA 产生两种或更多种信使 RNA（mRNA），迅速被光调控。然而，光调控 AS 的详细机制尚不清楚。在这项研究中，我们证明了组蛋白 3 赖氨酸 36 三甲基化（H3K36me3）在特定基因座对光的快速和差异反应，以及它们的转录物在苔藓植物Physcomitrella patens 中光调控的内含子保留（IR）。然而，暴露于光下后 H3K36me3 的水平与 IR 事件的水平呈反比。Physcomitrella patens MORF 相关基因 1（PpMRG1），一种染色质衔接蛋白，在光照条件下与 H3K36me3 的结合亲和力高于黑暗条件下，并且被差异地靶向到表现出光响应 IR 的基因座。转录组分析表明，PpMRG1 参与光介导的 AS 调控。此外，PpMRG1 还参与红光介导的向光性反应。我们的结果表明，光调节组蛋白甲基化，导致 AS 模式的改变。染色质衔接蛋白 PpMRG1 可能参与光介导的 AS，揭示了染色质偶联的前体 mRNA 剪接调控是植物对环境变化响应的一个重要方面。
