TRAF3 enhances STING-mediated antiviral signaling during the innate immune activation of black carp

Abstract

Tumor necrosis factor receptor-associated factor 3 (TRAF3) is a main regulator of antiviral and anti-inflammatory pathways in mammals, which is considered to induce type I interferon (IFN) activation and negatively regulate the activation of the canonical and non-canonical NF-κB pathways. To elucidate its function in teleost fish, TRAF3 homologue of black carp (Mylopharyngodon piceus) has been cloned and characterized in this study. The open reading frame (ORF) of black carp TRAF3 (bcTRAF3) consists of 1722 nucleotides and bcTRAF3 contains 574 amino acids. bcTRAF3 protein migrated around 65 KDa in immunoblot analysis of both EPC and HEK293T cells. bcTRAF3 was identified as a cytosolic protein and suggested to form aggregates or be associated with vesicles scattering in the cytoplasm. It was interesting that both NF-κB and IFN transcription was activated by bcTRAF3 in reporter assay. When co-expressed with black carp STING (bcSTING), bcTRAF3 was redistributed in the cytoplasm and its subcellular location overlapped with that of bcSTING no matter what the cells was infected with GCRV or not, which suggested the association between these two molecules. bcSTING-mediated IFN production was up-regulated by bcTRAF3 in a dose dependent manner in reporter assay. Accordingly, EPC cells transfected with both bcSTING and bcTRAF3 showed enhanced antiviral activity comparing EPC cells expressing bcSTING alone. Taken together, the data generated in this paper supported the conclusion that bcTRAF3 was recruited into host innate immune activation and positively regulated bcSTING-mediated antiviral signaling.

Downregulation of miR-1388 Regulates the Expression of Antiviral Genes via Tumor Necrosis Factor Receptor (TNFR)-Associated Factor 3 Targeting Following poly(I:C) Stimulation in Silver Carp (Hypophthalmichthys molitrix)

“…Numerous studies have demonstrated the crucial role of TRAF3 , a multifunctional immune molecule, in antiviral innate immunity [ 26 , 27 ]. Acting as the adaptor protein that links MAVS to mitochondria, TRAF3 facilitates K63-linked ubiquitination, thereby activating IFN-I [ 11 ].…”

Molecular Characterization of Nine TRAF Genes in Yellow Catfish (Pelteobagrus fulvidraco) and Their Expression Profiling in Response to Edwardsiella ictaluri Infection

“…These results suggest that Pf _TRAF4a might play positive regulatory roles in NF-κB signaling like other species [55,73]. The number of RING finger, zinc finger, TRAF-BIRC_3, coiled-coil and MATH domains of grouper, black carp, Nile tilapia, human and yellow catfish TRAF2 proteins is 1-2-0-1-1, 1-0-1-0-1, 1-1-1-0-1, 1-1-1-0-1 and 1-2-1-0-1, respectively [66,[74][75][76]. Among them, the grouper [66] and the black carp [74] TRAF2 are localized in the cytoplasm, and the human [76] and Nile tilapia [75] TRAF2 are localized in the nucleus and cytoplasm.…”

Molecular cloning, identification and expression analysis of MDA5/MAVS/TRAF3/TANK/TBK1, five pivotal molecules of RLR signalling pathway in turbot ( Scophthalmus maximus )

“…However, the role of TRAF3 in teleost compared with its mammalian counterpart is still largely unknown. In recent years, the TRAF3 homologues have been cloned and characterized in several species for instance, common carp ( Cyprinus carpio ) (Feng et al, 2011) and humphead snapper ( Lutjanus sanguineus ) (Cai et al, 2015), black carp (Wang et al, 2018), Nile tilapia ( Oreochromis niloticus ) (Han et al, 2020). In previous studies, it has been reported that some of the key components of RLR signalling such as MAVS, TRAF3, TRIF and IRF3 are found to be associated with TANK, where TANK is recruited into regulating phosphorylation of IRF3 and IFN induction (Gatot et al, 2007; Guo & Cheng, 2007).…”