Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China.
College of Animal Science, Guizhou University, Guiyang, China.
Vet Res. 2019 Mar 20;50(1):22. doi: 10.1186/s13567-019-0640-4.
Nuclear localization of paramyxovirus proteins is crucial for virus life cycle, including the regulation of viral replication and the evasion of host immunity. We previously showed that a recombinant Newcastle disease virus (NDV) with nuclear localization signal mutation in the matrix (M) protein results in a pathotype change and attenuates viral pathogenicity in chickens. However, little is known about the nuclear localization functions of NDV M protein. In this study, the potential functions of the M protein in the nucleus were investigated. We first demonstrate that nuclear localization of the M protein could not only promote the cytopathogenicity of NDV but also increase viral RNA synthesis and transcription efficiency in DF-1 cells. Using microarray analysis, we found that nuclear localization of the M protein might inhibit host cell transcription, represented by numerous up-regulating genes associated with transcriptional repressor activity and down-regulating genes associated with transcriptional activator activity. The role of representative up-regulated gene prospero homeobox 1 (PROX1) and down-regulated gene aryl hydrocarbon receptor (AHR) in the replication of NDV was then evaluated. The results show that siRNA-mediated knockdown of PROX1 or AHR significantly reduced or increased the viral RNA synthesis and viral replication, respectively, demonstrating the important roles of the expression changes of these genes in NDV replication. Together, our findings demonstrate for the first time that nuclear localization of NDV M protein promotes virus replication by affecting viral RNA synthesis and transcription and inhibiting host cell transcription, improving our understanding of the molecular mechanism of NDV replication and pathogenesis.
副粘病毒蛋白的核定位对于病毒生命周期至关重要，包括病毒复制的调节和宿主免疫的逃逸。我们之前曾表明，基质（M）蛋白中核定位信号突变的重组新城疫病毒（NDV）会导致病原型改变并减轻鸡的病毒致病性。然而，对于 NDV M 蛋白的核定位功能知之甚少。在这项研究中，我们研究了 M 蛋白在核内的潜在功能。我们首先证明 M 蛋白的核定位不仅可以促进 NDV 的细胞病变效应，还可以提高 DF-1 细胞中的病毒 RNA 合成和转录效率。通过微阵列分析，我们发现 M 蛋白的核定位可能会抑制宿主细胞转录，这表现为与转录抑制因子活性相关的大量上调基因和与转录激活因子活性相关的下调基因。然后评估了 M 蛋白核定位的代表性上调基因 prospero 同源盒 1（PROX1）和下调基因芳香烃受体（AHR）在 NDV 复制中的作用。结果表明，siRNA 介导的 PROX1 或 AHR 敲低显著降低或增加了病毒 RNA 合成和病毒复制，分别证明了这些基因表达变化在 NDV 复制中的重要作用。总之，我们的研究结果首次表明，NDV M 蛋白的核定位通过影响病毒 RNA 合成和转录以及抑制宿主细胞转录来促进病毒复制，从而提高了我们对 NDV 复制和发病机制的分子机制的理解。
