Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
Ceva Animal Health, Greifswald-Insel Riems, Germany.
Sci Rep. 2023 Aug 21;13(1):10342. doi: 10.1038/s41598-023-36788-9.
African swine fever virus (ASFV) is a lethal animal pathogen that enters its host cells through endocytosis. So far, host factors specifically required for ASFV replication have been barely identified. In this study a genome-wide CRISPR/Cas9 knockout screen in porcine cells indicated that the genes RFXANK, RFXAP, SLA-DMA, SLA-DMB, and CIITA are important for productive ASFV infection. The proteins encoded by these genes belong to the major histocompatibility complex II (MHC II), or swine leucocyte antigen complex II (SLA II). RFXAP and CIITA are MHC II-specific transcription factors, whereas SLA-DMA/B are subunits of the non-classical MHC II molecule SLA-DM. Targeted knockout of either of these genes led to severe replication defects of different ASFV isolates, reflected by substantially reduced plating efficiency, cell-to-cell spread, progeny virus titers and viral DNA replication. Transgene-based reconstitution of SLA-DMA/B fully restored the replication capacity demonstrating that SLA-DM, which resides in late endosomes, plays a crucial role during early steps of ASFV infection.
非洲猪瘟病毒（ASFV）是一种致命的动物病原体，通过内吞作用进入宿主细胞。迄今为止，专门用于 ASFV 复制的宿主因子几乎没有被鉴定出来。在这项研究中，猪细胞中的全基因组 CRISPR/Cas9 敲除筛选表明，RFXANK、RFXAP、SLA-DMA、SLA-DMB 和 CIITA 基因对 ASFV 的有效感染很重要。这些基因编码的蛋白质属于主要组织相容性复合体 II（MHC II）或猪白细胞抗原复合物 II（SLA II）。RFXAP 和 CIITA 是 MHC II 特异性转录因子，而 SLA-DMA/B 是非经典 MHC II 分子 SLA-DM 的亚单位。这些基因中的任何一个基因的靶向敲除都会导致不同 ASFV 分离株的严重复制缺陷，这反映在明显降低的平板效率、细胞间传播、后代病毒滴度和病毒 DNA 复制上。基于转染体的 SLA-DMA/B 的重建完全恢复了复制能力，表明驻留在晚期内体中的 SLA-DM 在 ASFV 感染的早期步骤中起着至关重要的作用。
