Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493 Greifswald, Insel Riems, Germany.
Institute of Infectology, Friedrich-Loeffler-Institut, 17493 Greifswald, Insel Riems, Germany.
Viruses. 2021 Jun 10;13(6):1117. doi: 10.3390/v13061117.
The molecular mechanism affecting translocation of newly synthesized herpesvirus nucleocapsids from the nucleus into the cytoplasm is still not fully understood. The viral nuclear egress complex (NEC) mediates budding at and scission from the inner nuclear membrane, but the NEC is not sufficient for efficient fusion of the primary virion envelope with the outer nuclear membrane. Since no other viral protein was found to be essential for this process, it was suggested that a cellular machinery is recruited by viral proteins. However, knowledge on fusion mechanisms involving the nuclear membranes is rare. Recently, vesicle-associated membrane protein-associated protein B (VAPB) was shown to play a role in nuclear egress of herpes simplex virus 1 (HSV-1). To test this for the related alphaherpesvirus pseudorabies virus (PrV), we mutated genes encoding VAPB and VAPA by CRISPR/Cas9-based genome editing in our standard rabbit kidney cells (RK13), either individually or in combination. Single as well as double knockout cells were tested for virus propagation and for defects in nuclear egress. However, no deficiency in virus replication nor any effect on nuclear egress was obvious suggesting that VAPB and VAPA do not play a significant role in this process during PrV infection in RK13 cells.
影响新合成的疱疹病毒核衣壳从细胞核到细胞质易位的分子机制仍未完全阐明。病毒核出芽复合物（NEC）介导在内核膜上出芽和断裂，但 NEC 不足以有效融合初级病毒包膜与外核膜。由于没有发现其他病毒蛋白对这个过程是必需的，因此推测病毒蛋白招募了一种细胞机制。然而，关于涉及核膜的融合机制的知识很少。最近，囊泡相关膜蛋白相关蛋白 B（VAPB）被证明在单纯疱疹病毒 1（HSV-1）的核出芽中发挥作用。为了检验这一点，我们使用基于 CRISPR/Cas9 的基因组编辑在我们的标准兔肾细胞（RK13）中分别或组合突变编码 VAPB 和 VAPA 的基因。对单敲除和双敲除细胞进行病毒繁殖和核出芽缺陷测试。然而，病毒复制没有明显缺陷，也没有对外核出芽产生影响，这表明 VAPB 和 VAPA 在 RK13 细胞中 PrV 感染期间的这个过程中没有发挥重要作用。
