The 3C protease of enterovirus A71 counteracts the activity of host zinc-finger antiviral protein (ZAP)

Abstract

Enterovirus A71 (EV-A71) is a positive-strand RNA virus that causes hand-foot-mouth disease and neurological complications in children and infants. Although the underlying mechanisms remain to be further defined, impaired immunity is thought to play an important role. The host zinc-finger antiviral protein (ZAP), an IFN-stimulated gene product, has been reported to specifically inhibit the replication of certain viruses. However, whether ZAP restricts the infection of enteroviruses remains unknown. Here, we report that EV-A71 infection upregulates ZAP mRNA in RD and HeLa cells. Moreover, ZAP overexpression rendered 293 T cells resistant to EV-A71 infection, whereas siRNA-mediated depletion of endogenous ZAP enhanced EV-A71 infection. The EV-A71 infection stimulated site-specific proteolysis of two ZAP isoforms, leading to the accumulation of a 40 kDa N-terminal ZAP fragment in virus-infected cells. We further revealed that the 3C protease (3Cpro) of EV-A71 mediates ZAP cleavage, which requires protease activity. Furthermore, ZAP variants with single amino acid substitutions at Gln-369 were resistant to 3Cpro cleavage, implying that Gln-369 is the sole cleavage site in ZAP. Moreover, although ZAP overexpression inhibited EV-A71 replication, the cleaved fragments did not show this effect. Our results indicate that an equilibrium between ZAP and enterovirus 3Cpro controls viral infection. The findings in this study suggest that viral 3Cpro mediated ZAP cleavage may represent a mechanism to escape host antiviral responses.

Inhibition of Japanese encephalitis virus infection by the host zinc-finger antiviral protein

“…HSV-1 UL41 endoribonuclease was identified as an antagonist of human ZAP by degrading its mRNA [ 17 ]. Enterovirus 71 3C protease mediates the cleavage of ZAP protein [ 18 ]. In our hands, DENV neither downregulated the expression of ZAP nor blocked the antiviral activity of ZAP ( S4 and S5 Figs).…”

The impact of PARPs and ADP-ribosylation on inflammation and host–pathogen interactions

“…As such, most of its antiviral activity is independent of ADP-ribosylation. Since its discovery, ZAP has been shown to inhibit the replication of several viral families, including retroviruses, alphaviruses, filoviruses, picornaviruses, herpesviruses, arteriviruses, orthomyxoviruses, flaviviruses, and hepatitis B virus (Bick et al 2003;Muller et al 2007;Zhu et al 2011;Wang et al 2012;Xuan et al 2012;Mao et al 2013;Xuan et al 2013;Li et al 2015Li et al , 2015aChiu et al 2018;Xie et al 2018;Zhao et al 2019). ZAP is transcribed into four different isoforms, with ZAPL and ZAPS being the most studied .…”

One Step Ahead: Herpesviruses Light the Way to Understanding Interferon-Stimulated Genes (ISGs)

“…ZAP exerts antiviral activity against a diverse range of viruses such as retroviruses, alphaviruses, filoviruses, hepatitis B virus and Japanese encephalitis virus by binding to RNA and indirectly mediating its degradation (Bick et al, 2003;Muller et al, 2007;Zhu et al, 2011;Mao et al, 2013;Takata et al, 2017;Chiu et al, 2018). However, ZAP fails to control other viruses, e.g., influenza A virus (Liu et al, 2015;Tang et al, 2017) or enterovirus A71 (Xie et al, 2018).…”