Structure of plant RNA-DEPENDENT RNA POLYMERASE 2, an enzyme involved in small interfering RNA production
Structure of plant RNA-DEPENDENT RNA POLYMERASE 2, an enzyme involved in small interfering RNA production
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DOI：
10.1093/plcell/koac067
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发表时间：
2022-02-21
期刊：
影响因子：
11.6
通讯作者：
Du, Jiamu
中科院分区：
文献类型：
--
作者：
Du, Xuan;Yang, Zhenlin;Du, Jiamu
在植物中，小干扰 RNA (siRNA) 的生物发生需要一系列依赖于 RNA 的 RNA 聚合酶，将单链 RNA (ssRNA) 转化为双链 RNA (dsRNA)，随后由 Dicer 核酸内切酶将其切割成确定的长度。在这里，我们确定了玉米 (Zea mays) RNA 依赖性 RNA 聚合酶 2 (ZmRDR2) 的闭合和开放构象的结构。 ZmRDR2 的核心催化区域拥有典型的 DNA 依赖性 RNA 聚合酶 (DdRP) 催化位点，表明 DdRP 和植物 RDR 家族蛋白之间存在共享的 RNA 生产机制。 Apo-ZmRDR2采用高度紧凑的结构，代表非活性的封闭构象。相比之下，添加RNA会诱导ZmRDR2头结构域发生显着的构象变化，从而打开RNA结合隧道，表明这是ZmRDR2的主动延伸构象。总体而言，我们的结构研究捕获了 ZmRDR2 的活性和非活性构象，为植物 siRNA 生产过程中 dsRNA 合成的分子机制提供了见解。玉米 RDR2 的闭合和开放构象结构为该 RDR 家族 RNA 聚合酶产生双链小干扰 RNA 的分子基础提供了见解。
In plants, the biogenesis of small interfering RNA (siRNA) requires a family of RNA-dependent RNA polymerases that convert single-stranded RNA (ssRNA) into double-stranded RNA (dsRNA), which is subsequently cleaved into defined lengths by Dicer endonucleases. Here, we determined the structure of maize (Zea mays) RNA-DEPENDENT RNA POLYMERASE 2 (ZmRDR2) in the closed and open conformations. The core catalytic region of ZmRDR2 possesses the canonical DNA-dependent RNA polymerase (DdRP) catalytic sites, pointing to a shared RNA production mechanism between DdRPs and plant RDR-family proteins. Apo-ZmRDR2 adopts a highly compact structure, representing an inactive closed conformation. By contrast, adding RNA induced a significant conformational change in the ZmRDR2 Head domain that opened the RNA binding tunnel, suggesting this is an active elongation conformation of ZmRDR2. Overall, our structural studies trapped both the active and inactive conformations of ZmRDR2, providing insights into the molecular mechanism of dsRNA synthesis during plant siRNA production.The structure of maize RDR2 in both the closed and open conformations provides insights into the molecular basis of double-stranded small interfering RNA production by this RDR family RNA polymerase.