在这项研究中，该课题组人员发现去分支的幼虫RNA可以阻止21和22核苷酸幼虫衍生的小干扰RNA （lasiRNAs）的产生，这些小干扰RNA可以抑制外显子siRNAs的爆发，从而保护发育和防御反应。LasiRNA生物发生依赖于RNA依赖的RNA聚合酶和Dicer样蛋白（DCLs）。当病原体感染和DBR1功能障碍时，许多植物RNA被DCL4和DCL2劫持并加工成专门针对免疫基因的siRNA，最终破坏植物的防御反应。总的来说，DBR1介导的分枝RNA去除是一种保护机制，可以防止植物中基于小RNA的防御系统的激活。
据了解，Lariat RNA是由内含子在前信使RNA剪接过程中形成的，之后它们被脱分枝酶DBR1降解。DBR1的损伤导致发育停滞，但其机制尚不清楚。
附：英文原文
Title: Lariat RNA debranching prevents harmful siRNA burst in plants
Author: Qi Tang, Chenxi Ding, Xiaotuo Zhang, Taiyun Wang, Mengjie Zhu, Ruixue Cui, Wenya Yang, Jinbiao Ma, Guodong Ren, Xiaoming Zhang, Binglian Zheng
Issue&Volume: 2026-06-25
Abstract: Lariat RNAs are formed from introns during pre–messenger RNA splicing, after which they are degraded by the debranching enzyme DBR1. Impairment of DBR1 leads to developmental arrest, yet the mechanism remains unclear. In this study, we found that debranching of lariat RNA prevents production of 21- and 22-nucleotide lariat-derived small interfering RNAs (lasiRNAs), which causes a burst of exonic siRNAs, thereby safeguarding development and defense response. LasiRNA biogenesis relied on RNA-dependent RNA polymerases and Dicer-like proteins (DCLs). Upon pathogen infection and dysfunction of DBR1, many lariat RNAs were hijacked by DCL4 and DCL2 and processed into siRNAs that particularly target immunity genes, ultimately disrupting plant defense responses. Collectively, DBR1-mediated lariat RNA removal serves as a protective mechanism to prevent the activation of a small RNA–based defense system in plants.
DOI: aeb4938
Source: https://www.science.org/doi/10.1126/science.aeb4938