Gamil Amr A A, Xu Cheng, Mutoloki Stephen, Evensen Øystein
Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep., 0033 Oslo, Norway.
Viruses. 2016 Jun 21;8(6):173. doi: 10.3390/v8060173.
The double-stranded RNA-activated protein kinase R (PKR) is a Type I interferon (IFN) stimulated gene that has important biological and immunological functions. In viral infections, in general, PKR inhibits or promotes viral replication, but PKR-IPNV interaction has not been previously studied. We investigated the involvement of PKR during infectious pancreatic necrosis virus (IPNV) infection using a custom-made rabbit antiserum and the PKR inhibitor C16. Reactivity of the antiserum to PKR in CHSE-214 cells was confirmed after IFNα treatment giving an increased protein level. IPNV infection alone did not give increased PKR levels by Western blot, while pre-treatment with PKR inhibitor before IPNV infection gave decreased eukaryotic initiation factor 2-alpha (eIF2α) phosphorylation. This suggests that PKR, despite not being upregulated, is involved in eIF2α phosphorylation during IPNV infection. PKR inhibitor pre-treatment resulted in decreased virus titers, extra- and intracellularly, concomitant with reduction of cells with compromised membranes in IPNV-permissive cell lines. These findings suggest that IPNV uses PKR activation to promote virus replication in infected cells.
双链RNA激活蛋白激酶R（PKR）是一种I型干扰素（IFN）刺激基因，具有重要的生物学和免疫学功能。在病毒感染中，一般来说，PKR抑制或促进病毒复制，但PKR与传染性胰腺坏死病毒（IPNV）的相互作用此前尚未被研究。我们使用定制的兔抗血清和PKR抑制剂C16研究了PKR在传染性胰腺坏死病毒（IPNV）感染过程中的作用。在IFNα处理使PKR蛋白水平升高后，证实了抗血清与CHSE - 214细胞中PKR的反应性。通过蛋白质印迹法，单独的IPNV感染并未使PKR水平升高，而在IPNV感染前用PKR抑制剂预处理则使真核起始因子2α（eIF2α）的磷酸化水平降低。这表明，尽管PKR未被上调，但在IPNV感染期间它参与了eIF2α的磷酸化过程。PKR抑制剂预处理导致细胞内外病毒滴度降低，同时IPNV允许性细胞系中膜受损的细胞数量减少。这些发现表明，IPNV利用PKR激活来促进病毒在感染细胞中的复制。
