Proteinase 2Apro Is Essential for Enterovirus Replication in Type I Interferon-Treated Cells

Department of Microbiology, Columbia University College of Physicians, New York, NY 10032, USA.
Journal of Virology (Impact Factor: 4.44). 03/2009; 83(9):4412-22. DOI: 10.1128/JVI.02177-08
Source: PubMed


The Picornaviridae family comprises a diverse group of small RNA viruses that cause a variety of human and animal diseases. Some of these viruses are known to induce cleavage of components of the innate immune system and to inhibit steps in the interferon pathway that lead to the production of type I interferon. There has been no study of the effect of picornaviral infection on the events that occur after interferons have been produced. To determine whether members of the Enterovirus genus can antagonize the antiviral activity of interferon-stimulated genes (ISGs), we pretreated cells with alpha interferon (IFN-alpha) and then infected the cells with poliovirus type 1, 2, or 3; enterovirus type 70; or human rhinovirus type 16. We found that these viruses were able to replicate in IFN-alpha-pretreated cells but that replication of vesicular stomatitis virus, a Rhabdovirus, and encephalomyocarditis virus (EMCV), a picornavirus of the Cardiovirus genus, was completely inhibited. Although EMCV is sensitive to IFN-alpha, coinfection of cells with poliovirus and EMCV leads to EMCV replication in IFN-alpha-pretreated cells. The enteroviral 2A proteinase (2A(pro)) is essential for replication in cells pretreated with interferon, because amino acid changes in this protein render poliovirus sensitive to IFN-alpha. The addition of the poliovirus 2A(pro) gene to the EMCV genome allowed EMCV to replicate in IFN-alpha-pretreated cells. These results support an inhibitory role for 2A(pro) in the most downstream event in interferon signaling, the antiviral activities of ISGs.

17 Reads
  • Source
    • "EV71 2A is a cysteine protease that cleaves the eukaryotic initiation factor 4GI, a key factor for host protein synthesis [32]. Moreover, transient expression of EV71 2A protease alone also induced apoptosis [33,34]. In the presence or absence of CHA at 20 µg/ml, the gene expressions of EV71 VP1, 3C and 3D were strongly induced at 4 and 8 h p.i. after EV71 infection and CHA treatment. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Enterovirus 71 (EV71) is an etiology for a number of diseases in humans. Traditional Chinese herbs have been reported to be effective for treating EV71 infection. However, there is no report about the antiviral effects of CHA against EV71. In this study, plaque reduction assay demonstrated that the inhibitory concentration 50% (IC50) of CHA on EV71 replication is 6.3 µg/ml. When both CHA (20 µg/ml) and EV71 were added, or added post-infection at different time points, CHA was able to effectively inhibit EV71 replication between 0 and 10 h. In addition, CHA inhibited EV71 2A transcription and translation in EV71-infected RD cells, but did not affect VP1, 3C, and 3D expression. Furthermore, CHA inhibited secretions of IL-6, TNF-α, IFN-γ and MCP-1 in EV71-infected RD cells. Altogether, these results revealed that CHA may have antiviral properties for treating EV71 infection.
    PLoS ONE 09/2013; 8(9):e76007. DOI:10.1371/journal.pone.0076007 · 3.23 Impact Factor
  • Source
    • "It has been shown that virus-associated rearrangements in infrastructure and metabolism of the infected cell, although similar in appearance, could be driven by non-homologous viral 'security proteins' (Romanova et al., 2009). For example, the unrelated poliovirus protease 2A pro and cardiovirus leader protein have been shown to affect interferon signalling (Hato et al., 2007; Morrison & Racaniello, 2009), nuclear transport (Bardina et al., 2009; Belov et al., 2004; Castello et al., 2009; Fig. 1. Labelling of nascent RNAs in picornavirus-infected HeLa cells. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Both entero- and cardioviruses have been shown to suppress host mRNA synthesis. Enteroviruses are also known to inhibit the activity of rRNA genes, whereas this ability of cardioviruses is under debate. This study reported that mengovirus (a cardiovirus) suppressed rRNA synthesis but less efficiently than poliovirus (an enterovirus). In contrast to poliovirus infection, the incorporation of BrUTP, fluorouridine and [14C]uridine in rRNA precursors was observed even during the late stages of mengovirus infection, although at a significantly reduced level. The cleavage of TATA-binding protein, considered to be one of the central events in poliovirus-induced transcription shutoff, was not detected in mengovirus-infected cells, indicating a difference in the mechanisms of host RNA synthesis inhibition caused by these viruses. The results also showed that functional leader protein is redundant for the suppression of host RNA synthesis by cardiovirus.
    Journal of General Virology 05/2010; 91(Pt 5):1239-44. DOI:10.1099/vir.0.017723-0 · 3.18 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Apoptosis is a common antiviral defensive mechanism that potentially limits viral reproduction and spread. Many viruses possess apoptosis-suppressing tools. Here, we show that the productive infection of HeLa cells with encephalomyocarditis virus (a cardiovirus) was not accompanied by full-fledged apoptosis (although the activation of caspases was detected late in infection) but rather elicited a strong antiapoptotic state, as evidenced by the resistance of infected cells to viral and nonviral apoptosis inducers. The development of the antiapoptotic state appeared to depend on a function(s) of the viral leader (L) protein, since its mutational inactivation resulted in the efflux of cytochrome c from mitochondria, the early activation of caspases, and the appearance of morphological and biochemical signs of apoptosis in a significant proportion of infected cells. Infection with both wild-type and L-deficient viruses induced the fragmentation of mitochondria, which in the former case was not accompanied with cytochrome c efflux. Although the exact nature of the antiapoptotic function(s) of cardioviruses remains obscure, our results suggested that it includes previously undescribed mechanisms operating upstream and possibly downstream of the mitochondrial level, and that L is involved in the control of these mechanisms. We propose that cardiovirus L belongs to a class of viral proteins, dubbed here security proteins, whose roles consist solely, or largely, in counteracting host antidefenses. Unrelated L proteins of other picornaviruses as well as their highly variable 2A proteins also may be security proteins. These proteins appear to be independent acquisitions in the evolution of picornaviruses, implying multiple cases of functional (though not structural) convergence.
    Journal of Virology 06/2009; 83(14):7273-84. DOI:10.1128/JVI.00467-09 · 4.44 Impact Factor
Show more


17 Reads
Available from