Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
J Virol. 2019 Feb 5;93(4). doi: 10.1128/JVI.01579-18. Print 2019 Feb 15.
Defective viral genomes (DVGs) generated during RNA virus replication determine infection outcome by triggering innate immunity, diminishing virulence, and, in many cases, facilitating the establishment of persistent infections. Despite their critical role during virus-host interactions, the mechanisms regulating the production and propagation of DVGs are poorly understood. Visualization of viral genomes using RNA fluorescent hybridization revealed a striking difference in the intracellular localization of DVGs and full-length viral genomes during infections with the paramyxovirus Sendai virus. In cells enriched in full-length virus, viral genomes clustered in a perinuclear region and associated with cellular trafficking machinery, including microtubules and the GTPase Rab11a. However, in cells enriched in DVGs, defective genomes distributed diffusely throughout the cytoplasm and failed to interact with this cellular machinery. Consequently, cells enriched in full-length genomes produced both DVG- and full-length-genome-containing viral particles, while DVG-high cells poorly produced viral particles yet strongly stimulated antiviral immunity. These findings reveal the selective production of both standard and DVG-containing particles by a subpopulation of infected cells that can be differentiated by the intracellular localization of DVGs. This study highlights the importance of considering this functional heterogeneity in analyses of virus-host interactions during infection. Defective viral genomes (DVGs) generated during Sendai virus infections accumulate in the cytoplasm of some infected cells and stimulate antiviral immunity and cell survival. DVGs are packaged and released as defective particles and have a significant impact on infection outcome. We show that the subpopulation of DVG-high cells poorly engages the virus packaging and budding machinery and do not effectively produce viral particles. In contrast, cells enriched in full-length genomes are the primary producers of both standard and defective viral particles during infection. This study demonstrates heterogeneity in the molecular interactions occurring within infected cells and highlights distinct functional roles for cells as either initiators of immunity or producers and perpetuators of viral particles depending on their content of viral genomes and their intracellular localization.
缺陷型病毒基因组 (DVGs) 在 RNA 病毒复制过程中产生，通过触发先天免疫、降低病毒毒力，并且在许多情况下促进持续性感染的建立，从而决定感染结果。尽管它们在病毒-宿主相互作用中具有关键作用，但调控 DVGs 产生和传播的机制仍知之甚少。使用 RNA 荧光杂交技术对病毒基因组进行可视化，揭示了在副黏病毒仙台病毒感染过程中，DVGs 和全长病毒基因组在细胞内的定位存在显著差异。在富含全长病毒的细胞中，病毒基因组聚集在核周区域，并与包括微管和 GTPase Rab11a 在内的细胞运输机制相关。然而，在富含 DVGs 的细胞中，缺陷型基因组在细胞质中弥散分布，并且不能与这些细胞机制相互作用。因此，富含全长基因组的细胞产生了含有 DVG 和全长基因组的病毒颗粒，而富含 DVG 的细胞产生的病毒颗粒很少，但强烈刺激了抗病毒免疫。这些发现揭示了受感染细胞的亚群选择性地产生标准和含有 DVG 的颗粒，这可以通过 DVGs 的细胞内定位来区分。本研究强调了在感染过程中分析病毒-宿主相互作用时考虑这种功能异质性的重要性。
