The Zhongzhou Laboratory for Integrative Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China.
Sanya Institute, Henan University, Sanya, 572025, China.
Nat Commun. 2024 Sep 3;15(1):7696. doi: 10.1038/s41467-024-52034-w.
Heat stress (HS) poses a significant challenge to plant survival, necessitating sophisticated molecular mechanisms to maintain cellular homeostasis. Here, we identify SICKLE (SIC) as a key modulator of HS responses in Arabidopsis (Arabidopsis thaliana). SIC is required for the sequestration of RNA DEBRANCHING ENZYME 1 (DBR1), a rate-limiting enzyme of lariat intronic RNA (lariRNA) decay, into stress granules (SGs). The sequestration of DBR1 by SIC enhances the accumulation of lariRNAs, branched circular RNAs derived from excised introns during pre-mRNA splicing, which in turn promote the transcription of their parental genes. Our findings further demonstrate that SIC-mediated DBR1 sequestration in SGs is crucial for plant HS tolerance, as deletion of the N-terminus of SIC (SIC) impairs DBR1 sequestration and compromises plant response to HS. Overall, our study unveils a mechanism of transcriptional regulation in the HS response, where lariRNAs are enriched through DBR1 sequestration, ultimately promoting the transcription of heat stress tolerance genes.
热应激（HS）对植物的生存构成了重大挑战，需要复杂的分子机制来维持细胞内稳态。在这里，我们鉴定出 SICKLE（SIC）是拟南芥（Arabidopsis thaliana）HS 反应的关键调节剂。SIC 是将 RNA 去分支酶 1（DBR1）隔离到应激颗粒（SG）中的必需因子，DBR1 是剪接体 RNA （lariRNA）降解的限速酶。SIC 将 DBR1 隔离，促进了分支环状 RNA 的积累，这些环状 RNA 是由前体 mRNA 剪接过程中切除的内含子衍生而来的，进而促进其亲本基因的转录。我们的研究结果进一步表明，SIC 介导的 DBR1 在 SG 中的隔离对于植物的 HS 耐受至关重要，因为 SIC 的 N 端缺失（SIC）会损害 DBR1 的隔离并损害植物对 HS 的反应。总的来说，我们的研究揭示了 HS 反应中一种转录调控的机制，其中通过 DBR1 的隔离富集了 lariRNAs，最终促进了热应激耐受基因的转录。
