Herpes Simplex Virus 1 UL34 Mutants That Affect Membrane Budding Regulation and Nuclear Lamina Disruption
Herpes Simplex Virus 1 UL34 Mutants That Affect Membrane Budding Regulation and Nuclear Lamina Disruption
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DOI：
10.1128/jvi.00873-21
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发表时间：
2021-06
影响因子：
5.4
通讯作者：
Amber Vu;Shaowen White;Tiffany Cassmann;R. Roller
中科院分区：
文献类型：
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作者：
Amber Vu;Shaowen White;Tiffany Cassmann;R. Roller
疱疹病毒核输出是一个复杂的、受调控的过程，由两种病毒蛋白协调，这两种病毒蛋白在疱疹病毒中保守，形成异二聚体核输出复合物（NEC）。NEC驱动内核膜上衣壳的出芽，并招募其他病毒和宿主细胞蛋白来破坏核层、膜分裂和融合。疱疹病毒核出口的核包膜出芽可能受到负调控，因为pUL31/pUL34核出口复合体异二聚体在体外表达或在人工膜上表达时可以诱导无衣壳的膜出芽，但在感染细胞中却不能。我们之前描述了一个在R158和R161上含有丙氨酸取代的pUL34突变体，它表现出生长受损，pUL31/pUL34相互作用受损，出芽不受调节。在这里，我们确定了个体替换对这些表型的表型贡献。单独的替代都不能再现受损的生长或核输出复合体（NEC）相互作用表型。然而，任何一种替代都可以完全复制不受管制的出芽表型，这表明不受管制的出芽可能不会实质上损害病毒复制。此外，R158A取代导致NEC重新定位到核内点状结构，并将核层蛋白A/C招募到这些结构中，这表明该残基可能对核层蛋白扩散的激酶招募很重要。疱疹病毒核输出是一个复杂的、受调控的过程，由两种病毒蛋白协调，这两种病毒蛋白在疱疹病毒中形成异二聚体核输出复合体（NEC）。NEC驱动内核膜上衣壳的出芽，并招募其他病毒和宿主细胞蛋白来破坏核层、膜分裂和融合。除膜出芽外，NEC个体活动的结构基础尚不清楚，膜出芽调控的基础也不清楚。在这里，我们探索了具有不受调节出芽表型的NEC突变体的特性，确定了该调节对病毒复制的重要性，并表征了核层破坏的结构要求。
Herpesvirus nuclear egress is a complex, regulated process coordinated by two virus proteins that are conserved among the herpesviruses that form a heterodimeric nuclear egress complex (NEC). The NEC drives budding of capsids at the inner nuclear membrane and recruits other viral and host cell proteins for disruption of the nuclear lamina, membrane scission, and fusion. ABSTRACT Nuclear envelope budding in herpesvirus nuclear egress may be negatively regulated, since the pUL31/pUL34 nuclear egress complex heterodimer can induce membrane budding without capsids when expressed ectopically or on artificial membranes in vitro, but not in the infected cell. We have previously described a pUL34 mutant that contained alanine substitutions at R158 and R161 and that showed impaired growth, impaired pUL31/pUL34 interaction, and unregulated budding. Here, we determine the phenotypic contributions of the individual substitutions to these phenotypes. Neither substitution alone was able to reproduce the impaired growth or nuclear egress complex (NEC) interaction phenotypes. Either substitution, however, could fully reproduce the unregulated budding phenotype, suggesting that misregulated budding may not substantially impair virus replication. In addition, the R158A substitution caused relocalization of the NEC to intranuclear punctate structures and recruited lamin A/C to these structures, suggesting that this residue might be important for recruitment of kinases for dispersal of nuclear lamins. IMPORTANCE Herpesvirus nuclear egress is a complex, regulated process coordinated by two virus proteins that are conserved among the herpesviruses that form a heterodimeric nuclear egress complex (NEC). The NEC drives budding of capsids at the inner nuclear membrane and recruits other viral and host cell proteins for disruption of the nuclear lamina, membrane scission, and fusion. The structural basis of individual activities of the NEC, apart from membrane budding, are not clear, nor is the basis of the regulation of membrane budding. Here, we explore the properties of NEC mutants that have an unregulated budding phenotype, determine the significance of that regulation for virus replication, and also characterize a structural requirement for nuclear lamina disruption.