A Bunyavirus-Inducible Ubiquitin Ligase Targets RNA Polymerase IV for Degradation during Viral Pathogenesis in Rice
A Bunyavirus-Inducible Ubiquitin Ligase Targets RNA Polymerase IV for Degradation during Viral Pathogenesis in Rice
复制标题
一种布尼亚病毒诱导的泛素连接酶在水稻病毒发病过程中靶向 RNA 聚合酶 IV 进行降解
DOI：
10.1016/j.molp.2020.02.010
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发表时间：
2020-06-01
期刊：
影响因子：
27.5
通讯作者：
Wu, Jian-Guo
中科院分区：
文献类型：
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作者：
Zhang, Chao;Wei, Ying;Wu, Jian-Guo
泛素-蛋白酶体系统（ubiquitin-proteasome system，UPS）是真核生物中一种重要的翻译后调控机制，控制着细胞的多种功能。在这里，我们表明，稳定表达的P3蛋白编码的水稻草矮病毒（RGSV），负链RNA病毒在布尼亚病毒目，导致发育异常的RGSV引起的疾病症状，如矮化和过量分蘖，在转基因水稻植株。我们发现P3的转基因表达和RGSV感染都诱导水稻核RNA聚合酶Dia（OsNRPD 1a）的泛素化和UPS依赖性降解，OsNRPD 1a是植物特异性RNA聚合酶IV（Pol IV）的最大亚基的两个直向同源物之一，其是RNA指导的DNA甲基化（RdDM）所必需的。此外，我们确定了P3诱导的U-box型E3泛素连接酶，命名为P3诱导蛋白1（P3 IP 1），它与OsNRPD 1a相互作用，并介导其泛素化和UPS依赖的降解在体外和体内。值得注意的是，OsNRPD 1的敲低和P3 IP 1在水稻植株中的过表达都诱导了与RGSV病害类似的发育表型。综上所述，我们的研究结果揭示了一种新的毒力机制，即植物病原体靶向宿主RNA Pol IV进行UPS依赖性降解以诱导疾病症状。我们的研究还确定了E3泛素连接酶，其靶向RdDM复合体NRPD 1的UPS介导的降解水稻。
The ubiquitin-proteasome system (UPS) is an important post-translational regulatory mechanism that controls many cellular functions in eukaryotes. Here, we show that stable expression of P3 protein encoded by Rice grassy stunt virus (RGSV), a negative-strand RNA virus in the Bunyavirales, causes developmental abnormities similar to the disease symptoms caused by RGSV, such as dwarfing and excess tillering, in transgenic rice plants. We found that both transgenic expression of P3 and RGSV infection induce ubiquitination and UPS-dependent degradation of rice NUCLEAR RNA POLYMERASE Dia (OsNRPD1a), one of two orthologs of the largest subunit of plant-specific RNA polymerase IV (Pol IV), which is required for RNA-directed DNA methylation (RdDM). Furthermore, we identified a P3-inducible U-box type E3 ubiquitin ligase, designated as P3-inducible protein 1 (P3IP1), which interacts with OsNRPD1a and mediates its ubiquitination and UPS-dependent degradation in vitro and in vivo. Notably, both knockdown of OsNRPD1 and overexpression of P3IP1 in rice plants induced developmental phenotypes similar to RGSV disease symptomss. Taken together, our findings reveal a novel virulence mechanism whereby plant pathogens target host RNA Pol IV for UPS-dependent degradation to induce disease symptoms. Our study also identified an E3 ubiquitin ligase, which targets the RdDM compotent NRPD1 for UPS-mediated degradation in rice.