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Signal transducer and activator of transcription 1 (STAT1) plays a critical role in immune response, human STAT1 as a transcriptional suppressor of autophagy genes and autophagic activity. Classical swine fever virus (CSFV)-infected induce autophagy, leading to immune evasion. However, there are limited reports on the function of porcine STAT1 in autophagy during CSFV infection. There is also lack of suitable in vitro models for studying porcine STAT1. The objective of this study was to establish porcine PK-15 STAT1-/- and 3D4/21 STAT1-/- cell lines using the CRISPR/Cas9 system to investigate the function of the STAT1 in autophagy. The PK-15STAT1-/- and 3D4/21STAT1-/- cell lines, featuring homozygous knockout of STAT1 gene were successfully constructed using the CRISPR/Cas9 editing system. The knockout efficiency determined to be 82.4% and 81.1%, respectively. Infection with CSFV in porcine PK-15STAT1-/- and 3D4/21STAT1-/- cells led to an observable increase in autophagosomes as evidenced by transmission electron microscope. Additionally, STAT1 knockout (STAT1-/-) by the CRISPR/Cas9 system upregulated the expression of ULK1, Beclin1, and LC3 genes, thereby enhancing autophagy during CSFV infection. Conversely, overexpression of STAT1 downregulated the expression of ULK1, Beclin1, and LC3 genes, leading to inhibition of autophagy during CSFV infection.The application of an autophagy dual-fluorescent-tracking plasmid demonstrated that STAT1 knockout enhanced autophagy accumulation during CSFV infection, while STAT1 overexpression inhibited it. Moreover, the 3D4/21STAT1-/- cell line proved to be a more suitable in vitro model compared to the PK-15STAT1-/- cell line for elucidating the involvement of STAT1 in autophagy during CSFV infection. [ABSTRACT FROM AUTHOR]

Microarray data reported elsewhere indicated that herpes simplex virus 1 induces the up-regulation of nuclear factor [kappa]B (NF-[kappa]B)-regulated genes, including that of its inhibitor, I[kappa]B[alpha], consistent with the reports that wild-type virus induces the activation of NF-[kappa]B. In this report we show that activation of NF-[kappa]B in infected cells is linked to the activation of protein kinase R (PKR). Specifically: (i) PKR is activated in infected cells although the effects of the activated enzyme on protein synthesis are negated by the viral gene [[gamma].sub.1.34.5], which encodes a protein phosphatase 1[alpha] accessory factor that enables the dephosphorylation of the [alpha] subunit of eukaryotic translation initiation factor 2. NF-[kappa]B is activated in wild-type murine embryonic fibroblasts but not in related PKR-null cells. (ii) In cells infected with a replication-competent [DELTA][[gamma].sub.1.34.5 mutant (R5104), but carrying a [U.sub.s.11] gene expressed early in infection, eukaryotic translation initiation factor 2[alpha] is not phosphorylated, and in vitro assays, PKR bound to the [U.sub.s.11] protein is not phosphorylated on subsequent addition of double-stranded RNA. Here we report that this mutant does not activate PKR, has no effect on the accumulation of I[kappa]B[alpha], and does not cause the translocation of NF-[kappa]B in infected cells. (iii) One hypothesis advanced for the activation of NF-[kappa]B is that it blocks apoptosis induced by viral gene products. The replication-competent R5104 mutant does not induce the programmed cell's death. We conclude that in herpes simplex virus 1-infected cells, activation of NF-[kappa]B depends on activation of PKR and that NF-[kappa]B is not required to block apoptosis in productively infected cells.

Microarray data reported elsewhere indicated that herpes simplex virus I induces the up-regulation of nuclear factor &key;B (NF-&key;B)regulated genes, including that of its inhibitor, I&key;Bα, consistent with the reports that wild-type virus induces the activation of NF-&key;B. In this report we show that activation of NF-&key;B in infected cells is linked to the activation of protein kinase R (PKR). Specifically: (i) PKR is activated in infected cells although the effects of the activated enzyme on protein synthesis are negated by the viral gene 1,134.5, which encodes a protein phosphatase la accessory factor that enables the dephosphorylation of the a subunit of eukaryotic translation initiation factor 2. NF-&key;B is activated in wild-type murine embryonic fibroblasts but not in related PKR-null cells. (ii) In cells infected with a replication-competent δγ134.5 mutant (R5104), but carrying a Us11 gene expressed early in infection, eukaryotic translation initiation factor 2α is not phosphorylated, and in in vitro assays, PKR bound to the Us11 protein is not phosphorylated on subsequent addition of double-stranded RNA. Here we report that this mutant does not activate PKR, has no effect on the accumulation of I&key;Bα, and does not cause the translocation of NF-&key;B in infected cells. (iii) One hypothesis advanced for the activation of NF-&key;B is that it blocks apoptosis induced by viral gene products. The replication-competent R5104 mutant does not induce the programmed cell's death. We conclude that in herpes simplex virus 1-infected cells, activation of NF-&key;B depends on activation of PKR and that NF-&key;B is not required to block apoptosis in productively infected cells. [ABSTRACT FROM AUTHOR]

Nucleoprotein (NP) is a major component of the viral ribonucleoprotein (vRNP) complex that is responsible for viral replication, transcription and packaging of influenza A virus. Phosphorylation of NP plays an important role during viral infection. In the present study, we identified threonine 188 (T188) as a novel phosphorylated residue in the NP of influenza A virus by using mass spectrometry. T188 is located within nuclear export signal 2 (NES2) which is chromosome region maintenance 1 (CRM1)-independent. We observed that the phosphorylation and dephosphorylation of residue T188 regulated viral replication by controlling NES2-dependent NP nuclear export and the polymerase activity of the vRNP complex. Our findings provide further insights for understanding the replication of influenza A virus. [ABSTRACT FROM AUTHOR]

Interferon (IFN)-stimulated gene 15 (ISG15) encodes a ubiquitin-like protein that is heavily involved in immune response elicitation. As an important member of interferon regulatory factor (IRF) family, IRF1 can activate the expression of multiple genes, including the human optineurin gene (Sudhakar et al., 2013). In this study, a sequence in the promoter region of the optineurin gene was compared to the 5' flanking region of the porcine isg15 gene. Porcine IRF1 also possesses antiviral activity against several swine viruses (Li et al., 2015), but the mechanism is not well understood. Herein, we report that porcine IRF1 and ISG15 were up-regulated in porcine kidney (PK-15) cells following stimulation with double-stranded RNA (dsRNA) or classical swine fever virus (CSFV) infection. We also found that siRNA-mediated knockdown of IRF1 expression resulted in lower ISG15 expression in response to polyinosinic:polycytidylic acid [poly(I:C)] or CSFV infection. The overexpression of IRF1 resulted in ISG15 up-regulation. IRF1 was shown to translocate to the nucleus in response to dsRNA stimulation. To further identify the functional domain of the isg15 gene that promotes IRF1 transcriptional activity, firefly luciferase and ISG15 reporter systems were constructed. The results of the firefly luciferase and ISG15 reporter assay suggested that IRF1 mediates the up-regulation of ISG15. Nucleotides -487 to -325, located in the 5' flanking region of the isg15 gene, constituted the promoter region of IRF1. ChIP assay indicated that IRF1 protein was able to interact with the DNA in the 5'fr of isg15 gene in cells. As an innate immune response protein with broad-spectrum antiviral activity, the up-regulation of ISG15 mediated by IRF1 in porcine cells is reported for the first time. These results warrant further investigation into the antiviral activity of porcine IRF1 against reported swine viruses., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The continued detection of zoonotic viral infections in bats has led to the microbial fauna of these mammals being studied at a greater level than ever before. Whilst numerous pathogens have been discovered in bat species, infection with lyssaviruses is of particular significance from a zoonotic perspective as, where human infection has been reported, it is invariably fatal. Here we review the detection of lyssaviruses within different bat species and overview what is understood regarding their maintenance and transmission following both experimental and natural infection. We discuss the relevance of these pathogens as zoonotic agents and the threat of newly discovered viruses to human populations.

Background: Classical swine fever virus (CSFV) can evade the immune response and establish chronic infection under natural and experimental conditions. Some genes related to antigen processing and presentation and to cytokine regulation are known to be involved in this response, but the precise mechanism through which each gene responds to CSFV infection remains unclear., Results: In this study, the amplification standard curve and corresponding linear regression equations for the genes SLA-2, TAP1, SLA-DR, Ii, CD40, CD80, CD86, IFN-α, and IFN-β were established successfully. Real-time RT-PCR was used to quantify the immune response gene transcription in PK-15 cells post CSFV infection. Results showed that: (1) immune response genes were generally down-regulated as a result of CSFV infection, and (2) the expression of SLA-2, SLA-DR, Ii and CD80 was significantly decreased (p < 0.001)., Conclusion: We conclude that in vitro infection with CSFV inhibits the transcription of host immune response genes. These findings may facilitate the development of effective strategies for controlling CSF.