IRF2 inhibits ZIKV replication by promoting FAM111A expression to enhance the host restriction effect of RFC3

Kai Ren,Xiaoqiong Duan,Ya Zhu,Shilin Li,Limin Chen,Honggang Sun,Shuang Li,Bin Li,Yujia Li

doi:10.1186/s12985-021-01724-8

Abstract

BackgroundAlthough interferon regulatory factor 2 (IRF2) was reported to stimulate virus replication by suppressing the type I interferon signaling pathway, because cell cycle arrest was found to promote viral replication, IRF2-regulated replication fork factor (FAM111A and RFC3) might be able to affect ZIKV replication. In this study, we aimed to investigate the function of IRF2, FAM111A and RFC3 to ZIKV replication and underlying mechanism.MethodssiIRF2, siFAM111A, siRFC3 and pIRF2 in ZIKV-infected A549, 2FTGH and U5A cells were used to explore the mechanism of IRF2 to inhibit ZIKV replication. In addition, their expression was analyzed by RT-qPCR and western blots, respectively.ResultsIn this study, we found IRF2 expression was increased in ZIKV-infected A549 cells and IRF2 inhibited ZIKV replication independent of type I IFN signaling pathway. IRF2 could activate FAM111A expression and then enhanced the host restriction effect of RFC3 to inhibit replication of ZIKV.ConclusionsWe speculated the type I interferon signaling pathway might not play a leading role in regulating ZIKV replication in IRF2-silenced cells. We found IRF2 was able to upregulate FAM111A expression and thus enhance the host restriction effect of RFC3 on ZIKV.

Highlights

Zika virus (ZIKV) belongs to the flaviviridae family, and can transmit from mosquitoes to humans to cause microcephaly and Guillain–Barré syndrome in most severeThe Interferon regulatory factor (IRF) family comprises nine members, including Interferon regulatory factor 1 (IRF1), interferon regulatory factor 2 (IRF2), IRF3, IRF4, IRF5, IRF6, IRF7, IRF8 and IRF9 [6]
IRF2 expression is increased in ZIKV‐infected A549 cells To investigate whether the expression levels of IRF2 were changed following ZIKV replication by time, A549 cells were infected with ZIKV at a multiplicity of infection (MOI) of 0.5. mRNA and protein expression levels of ZIKV and IRF2 were measured at 12, 24, 48 and 72 h-post-infection by RT-qPCR and western blots
To assess effect of mainly antiviral factor (ISGs) in ZIKV-infected A549 cells, we examine expression levels of Interferon-stimulated gene 15 (ISG15) and IFN-induced proteins with tetratricopeptide repeat (IFIT1) at different time (Fig. 1c, d). These results indicated that ZIKV can infect and replicate steadily in A549 cells and IRF2, ISG15 and IFIT1 expression was increased upon ZIKV infection

Summary

Introduction

The Interferon regulatory factor (IRF) family comprises nine members, including IRF1, IRF2, IRF3, IRF4, IRF5, IRF6, IRF7, IRF8 and IRF9 [6]. They participate in a variety of biological processes including antiviral. Type I Interferons (mainly IFNα/β) induce the expression of a few hundred interferon-stimulated genes (ISGs) by activating the Jak-STAT signaling pathway to exert its anti-viral effect [11]. Interferon regulatory factor 2 (IRF2) was reported to stimulate virus replication by suppressing the type I interferon signaling pathway, because cell cycle arrest was found to promote viral replication, IRF2regulated replication fork factor (FAM111A and RFC3) might be able to affect ZIKV replication. We aimed to investigate the function of IRF2, FAM111A and RFC3 to ZIKV replication and underlying mechanism

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Conclusion