Enzyme E2 from Chinese White Shrimp Inhibits Replication of White Spot Syndrome Virus and Ubiquitinates Its RING Domain Proteins

Abstract

Recent studies have shown that the ubiquitin (Ub) proteasome pathway (UPP) is closely related to immune defense. We have identified a ubiquitin-conjugating enzyme, E2, from the Chinese white shrimp, Fenneropenaeus chinensis (FcUbc). Injection of recombinant FcUbc protein (rFcUbc) reduced the mortality of shrimp infected with white spot syndrome virus (WSSV) and inhibited replication of WSSV. rFcUbc, but not a mutant FcUbc (mFcUbc), bound to WSSV RING domains (WRDs) from four potential E3 ligase proteins of WSSV in vitro. Importantly, rFcUbc could ubiquitinate the RING domains (named WRD2 and WRD3) of WSSV277 and WSSV304 proteins in vitro and the two proteins in WSSV-infected Drosophila melanogaster Schneider 2 (S2) cells. Furthermore, overexpression of FcUbc increased ubiquitination of WSSV277 and WSSV304 during WSSV infection. In summary, our study demonstrates that FcUbc from Chinese white shrimp inhibited WSSV replication and could ubiquitinate WSSV RING domain-containing proteins. This is the first report about antiviral function of Ubc E2 in shrimp.

Prohibitin Interacts with Envelope Proteins of White Spot Syndrome Virus and Prevents Infection in the Red Swamp Crayfish, Procambarus clarkii

“…Other reports have also shown that the recombinant protein could enter the hemocytes. For example, a recombinant immulectin-3 from the insect Manduca sexta translocates from hemolymph into hemocytes (43), and the recombinant shrimp ubiquitin-conjugating enzyme E2 enters the hemocytes by endocytosis (44). In the present study, we also found that rPcPHB1 could enter the hemocytes of crayfish (Fig.…”

SUMO-Conjugating Enzyme E2 UBC9 Mediates Viral Immediate-Early Protein SUMOylation in Crayfish To Facilitate Reproduction of White Spot Syndrome Virus

“…When the exogenous proteins enter the hemocytes, they could participate in intracellular reactions. In our previous study, injected recombinant proteins could be detected in prawn hemocytes by both Western blotting and immunocytochemistry (31). Similarly, fluorescein isothiocyanate (FITC)-labeled recombinant immulectin-3 (IML-3) of Manduca sexta injected into larvae presented as large particles in hemocytes, suggesting that it enters cells through an endocytic pathway (34).…”

“…Both tissues were homogenized thoroughly in buffer (50 mM Tris-HCl [pH 7.5], 1% protein inhibitor cocktail) and centrifuged at 10,000 ϫ g for 10 min at 4°C, and the supernatant was collected. The protein concentration of each sample was assayed using a spectrophotometer (GE Amersham Biosciences), the samples were mixed with Laemmli buffer (60 mM Tris-HCl [pH 6.8], 2% SDS, 10% glycerol, 5% ␤-mercaptoethanol, 0.01% bromophenol blue), and Western blotting was performed as previously described (31).…”

Molecular basis and genetic improvement of economically important traits in aquaculture animals

“…Significantly, some novel interferon-inducible genes have been found [121], and their functional roles and signaling pathways have been well understood in fish [122][123][124]. Additionally, several candidate genes, such as PKR [125], PKR-like (or called PKZ) [126], β-Defensin [127], TRBP [128], C-type lectin [129], Enzyme E2 [130], MDA5 and LGP2 [131], have been revealed to play crucial roles in the antiviral defense response of fish and shrimp.…”