ABSTRACT
Human UBL4A/GdX, encoding an ubiquitin-like protein, was shown in this study to be upregulated by viral infection and IFN stimulation. Then the functions of UBL4A in antiviral immune response were characterized. Overexpression of UBL4A promoted RNA virus-induced ISRE or IFN-ß or NF-κB activation, leading to enhanced type I IFN transcription and reduced virus replication. Consistently, knockdown of UBL4A resulted in reduced type I IFN transcription and enhanced virus replication. Additionally, overexpression of UBL4A promoted virus-induced phosphorylation of TBK1, IRF3, and IKKα/ß. Knockdown of UBL4A inhibited virus-induced phosphorylation of TBK1, IRF3, and IKKα/ß. Coimmunoprecipitation showed that UBL4A interacted with TRAF6, and this interaction was enhanced upon viral infection. Ubiquitination assays showed that UBL4A promoted the K63-linked ubiquitination of TRAF6. Therefore, we reveal a novel positive feedback regulation of UBL4A in innate immune response combating virus invasion by enhancing the K63-linked ubiquitination of TRAF6.
Subject(s)
Immunity, Innate , Intracellular Signaling Peptides and Proteins/immunology , Macrophages, Peritoneal/immunology , TNF Receptor-Associated Factor 6/immunology , Ubiquitination/immunology , Ubiquitins/immunology , Animals , HEK293 Cells , HeLa Cells , Humans , Intracellular Signaling Peptides and Proteins/genetics , Mice , TNF Receptor-Associated Factor 6/genetics , Ubiquitination/genetics , Ubiquitins/genetics , Viruses/genetics , Viruses/immunologyABSTRACT
Parainfluenza virus infection is a common respiratory illness in children. Although lncRNAs are novel regulators of virus-induced innate immunity, a systemic attempt to characterize the differential expression of lncRNAs upon parainfluenza virus infection is lacking. In this report, we identify 207 lncRNAs and 166 mRNAs differentially expressed in SeV-infected HEK293T cells by microarray. The functional annotation analysis reveals that differentially regulated transcripts are predominantly involved in the host antiviral response pathway. The lncRNAs with the potential to regulate SeV-induced antiviral response are identified by building the lncRNA-mRNA coexpression network. Furthermore, silencing lncRNA ENST00000565297 results in reduced type I IFN signaling upon SeV infection. These catalogs may facilitate future analysis of the functions of lncRNAs in innate immunity and related diseases.
Subject(s)
Immunity, Innate/genetics , Paramyxoviridae Infections/genetics , RNA, Long Noncoding/physiology , Child , Gene Expression Profiling , HEK293 Cells , Humans , Oligonucleotide Array Sequence Analysis , Paramyxoviridae Infections/immunology , RNA, Long Noncoding/genetics , Respirovirus Infections/genetics , Respirovirus Infections/immunology , Sendai virus/immunology , Sendai virus/pathogenicity , TranscriptomeABSTRACT
Ubiquitination and deubiquitination are important post-translational regulatory mechanisms responsible for fine tuning the antiviral signaling. In this study, we identified a deubiquitinase, the ubiquitin-specific peptidase 7/herpes virus associated ubiquitin-specific protease (USP7/HAUSP) as an important negative modulator of virus-induced signaling. Overexpression of USP7 suppressed Sendai virus and polyinosinic-polycytidylic acid and poly(deoxyadenylic-deoxythymidylic)-induced ISRE and IFN-ß activation, and enhanced virus replication. Knockdown or knockout of endogenous USP7 expression had the opposite effect. Coimmunoprecipitation assays showed that USP7 physically interacted with tripartite motif (TRIM)27. This interaction was enhanced after SeV infection. In addition, TNF receptor-associated factor family member-associated NF-kappa-B-binding kinase (TBK)-1 was pulled down in the TRIM27-USP7 complex. Overexpression of USP7 promoted the ubiquitination and degradation of TBK1 through promoting the stability of TRIM27. Knockout of endogenous USP7 led to enhanced TRIM27 degradation and reduced TBK1 ubiquitination and degradation, resulting in enhanced type I IFN signaling. Our findings suggest that USP7 acts as a negative regulator in antiviral signaling by stabilizing TRIM27 and promoting the degradation of TBK1.-Cai, J., Chen, H.-Y., Peng, S.-J., Meng, J.-L., Wang, Y., Zhou, Y., Qian, X.-P., Sun, X.-Y., Pang, X.-W., Zhang, Y., Zhang, J. USP7-TRIM27 axis negatively modulates antiviral type I IFN signaling.
