Hyponastic Leaves 1 protects pri-miRNAs from nuclear exosome attack
Hyponastic Leaves 1 protects pri-miRNAs from nuclear exosome attack
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Hyponastic Leaves 1 保护 pri-miRNA 免受核外泌体攻击
DOI：
10.1073/pnas.2007203117
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发表时间：
2020-07-21
影响因子：
11.1
通讯作者：
Ren, Guodong
中科院分区：
文献类型：
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作者：
Gao, Shuai;Wang, Jingyu;Ren, Guodong
植物microRNA（miRNAs）的生物发生发生在核切割体（D-bodies）中，其中核糖核酸酶III型酶Dicer-like 1（DCL 1）将miRNAs的初级转录物（pri-miRNAs）从碱基-环或环-碱基方向加工成miRNA/miRNA*（*，过客链）双链体。Hyponastic Leaves 1（HYL 1）是一种双链RNA结合蛋白，对于高效和准确的加工至关重要。然而，HYL 1是否具有额外的功能仍然未知。在这里，我们报告说，HYL 1在保护pri-miRNAs免受核外泌体攻击方面发挥着非经典的作用，除了确保加工。核质外泌体的两个辅助因子SOP 1或HEN 2的功能丧失显著抑制了hyl 1 -2的形态表型。值得注意的是，从环到碱基加工产生的成熟miRNA在hyl 1 sop 1和hyl 1 hen 2双突变体中部分但优先恢复。因此，环到碱基加工的pri-miRNA在双突变体中积累到更高的水平。此外，hyl 1 -2中的HEN 2功能障碍，而不是SOP 1功能障碍，导致许多碱基到环加工的pri-miRNAs过度积累，而它们各自的大多数miRNAs不受影响。总而言之，我们的研究结果揭示了外泌体在pri-miRNA生物发生中的拮抗作用，并揭示了HYL 1在稳定和加工pri-miRNA中的双重作用。
Biogenesis of plant microRNAs (miRNAs) takes place in nuclear dicing bodies (D-bodies), where the ribonulease III-type enzyme Dicer-like 1 (DCL1) processes primary transcripts of miRNAs (pri-miRNAs) into miRNA/miRNA* (*, passenger strand) duplexes from either base-to-loop or loop-to-base directions. Hyponastic Leaves 1 (HYL1), a double-stranded RNA-binding protein, is crucial for efficient and accurate processing. However, whether HYL1 has additional function remains unknown. Here, we report that HYL1 plays a noncanonical role in protecting pri-miRNAs from nuclear exosome attack in addition to ensuring processing. Loss of functions in SOP1 or HEN2, two cofactors of the nucleoplasmic exosome, significantly suppressed the morphological phenotypes of hyl1-2. Remarkably, mature miRNAs generated from loop-to-base processing were partially but preferentially restored in the hyl1 sop1 and hyl1 hen2 double mutants. Accordingly, loop-to-base-processed pri-miRNAs accumulated to higher levels in doublemutants. In addition, dysfunction of HEN2, but not of SOP1, in hyl1-2 resulted in overaccumulation of many base-to-loop-processed pri-miRNAs, with most of their respective miRNAs unaffected. In summary, our findings reveal an antagonistic action of exosome in pri-miRNA biogenesis and uncover dual roles of HYL1 in stabilizing and processing of pri-miRNAs.