(A) 293T cells were treated with 0.5 mM SA for 0.5 h and then treated with or without CHX for another 1 h. we also found that 3C protease blocked the SG formation by disrupting eIF4GI-G3BP1 interaction. Overall, our results demonstrate that SVV induces transient SG formation in an eIF2 phosphorylation and PKR-dependent manner, and that 3C protease inhibits SG formation by interfering eIF4GI-G3BP1 interaction. (1, 2). SVV was detected as a cell culture contaminant in 2002 in the United States and subsequently identified as a novel picornavirus closely related to members of the genus Cardiovirus (1). SVV genome SNS-032 (BMS-387032) contains Rabbit Polyclonal to Tau a single open reading frame (ORF) consisting of 6543 nt encoding a polyprotein, which is cleaved into 4 structural proteins forming the viral capsid and 8 non-structural proteins playing indispensable roles on viral replication (1). Since 2007, SVV infection has been a serious threat to the global swine industry and there is no effective vaccine to control the disease (3, 4). Regardless of its harm to swine industry, SVV has been tested as an oncolytic agent for human cancer treatment, which has been tested in phase II clinical trials. A better understanding of virus-host interactions will contribute to disease prevention and control and the improvement of the virus-based therapeutics for cancer treatment. Virus infection results in various cellular stress responses that modulate SNS-032 (BMS-387032) cellular gene expression by influencing the mRNA translation, localization and degradation (5). SG formation is one of the stress responses. There are four stress kinases involved in SG formation: double-stranded RNA (dsRNA)-dependent protein kinase (PKR) is activated by dsRNA during viral infection; protein kinase R-like endoplasmic reticulum kinase (PERK) senses unfolded proteins accumulation in the endoplasmic reticulum; heme-regulated inhibitor kinase (HRI) is activated when heme levels are changed by arsenite; and general control non-derepressible 2 kinase (GCN2) is activated under amino acid starvation (6). The activation of these kinases induces the phosphorylation of the alpha-subunit of eukaryotic initiation factor 2 (eIF2), which shuts up most of initiation of eukaryotic translation and inhibits the formation of eIF2-GTP-ternary complex (7). The initiation of mRNA translation is suppressed and polysomes are disassembled during SGs formation. Canonical SGs consist of translationally silent mRNA, 40S ribosomal subunits, eukaryotic initiation factors (eIFs) and multiple RNA-binding proteins (RBPs) such as Ras-GTPase-activating protein SH3-domain-binding protein 1 (G3BP1) and T-cell internal antigen 1 (TIA1), and G3BP1 and TIA1 play a pivotal role in SG formation (8, 9). However, SG formation can also be induced in an eIF2-independent manner by the natural product pateamine A, which inhibits ribosome recruitment and hydrogen peroxide-induced oxidative stress SNS-032 (BMS-387032) (10C12). Several studies have reported the relationship between virus infection and SG formation. During virus infection, SG formation is classified into 4 different patterns: no SG formation, stable SG formation, transient SG formation and alternate SG formation (13). Several viruses, such as Porcine reproductive and respiratory syndrome (PRRSV), Rabies virus (RV), and Newcastle disease virus (NDV), induce stable SG formation (14C16). Due to the inhibitory effect of SGs on majority of virus infection, many viruses have evolved various strategies to inhibit SG formation to promote efficient viral propagation. Influenza A virus (IAV) NS1 protein binds to dsRNA to inhibit the activation of PKR, resulting in the blockage of SG formation (17). Japanese Encephalitis Virus SNS-032 (BMS-387032) (JEV) Core protein interacts with Caprin-1 to block SG formation, thus promoting virus propagation (18). Feline calicivirus (FCV) blocks SG formation through the cleavage of G3BP1 by NS6 protein (19). Picornavirus 2A or L protein inhibits tSG formation by interfering with the eIF4GI-G3BP interaction (20). In addition, ECMV infection induces transient SG formation on account of the cleavage G3BP1by L protein (13). In the present study, we show that SVV infection induces transient SG formation in a PKR-eIF2 dependent manner. Although transient SG formation has no effect on SVV replication, SG core component G3BP1 is critical for the expression of cytokine genes induced by SVV. Importantly, our data indicate that SVV 3C blocks the SG formation by disrupting eIF4GI-G3BP1 interaction. Materials and Methods Cells and Viruses HEK 293T cells were.