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

Abstract

Successful viruses have evolved superior strategies to escape host defenses or exploit host biological pathways. Most of the viral immediate-early (ie) genes are essential for viral infection and depend solely on host proteins; however, the molecular mechanisms are poorly understood. In this study, we focused on the modification of viral IE proteins by the crayfish small ubiquitinrelated modifier (SUMO) and investigated the role of SUMOylation during the viral life cycle. SUMO and SUMO ubiquitin-conjugating enzyme 9 (UBC9) involved in SUMOylation were identified in red swamp crayfish (Procambarus clarkii). Both SUMO and UBC9 were upregulated in crayfish challenged with white spot syndrome virus (WSSV). Replication of WSSV genes increased in crayfish injected with recombinant SUMO or UBC9, but injection of mutant SUMO or UBC9 protein had no effect. Subsequently, we analyzed the mechanism by which crayfish SUMOylation facilitates WSSV replication. Crayfish UBC9 bound to all three WSSV IE proteins tested, and one of these IE proteins (WSV051) was covalently modified by SUMO in vitro. The expression of viral ie genes was affected and that of late genes was significantly inhibited in UBC9-silenced or SUMO-silenced crayfish, and the inhibition effect was rescued by injection of recombinant SUMO or UBC9. The results of this study demonstrate that viral IE proteins can be modified by crayfish SUMOylation, prompt the expression of viral genes, and ultimately benefit WSSV replication. Understanding of the mechanisms by which viruses exploit host components will greatly improve our knowledge of the virus-host "arms race" and contribute to the development of novel methods against virulent viruses.

RNA interference in shrimp and potential applications in aquaculture

“…Upon expression of this RNA, both the forward and reverse part will self-anneal, forming the dsRNA molecule (Yodmuang et al 2006). Using another strategy, target DNA is cloned in between two T7 promoter sequence on a vector such as Litmus 28i, Litmus 38i or L4440 (Sarathi et al 2008;Chen et al 2013;Treerattrakool et al 2013). The transformed HT115 (DE3) strain can eventually produce up to 45 lg dsRNA/1-OD600/mL E. coli culture (Posiri et al 2013), and large-scale in vivo dsRNA production is approximately one-fourth the cost of production using a commercial in vitro transcription kit (Saksmerprome et al 2009).…”

A novel L-type lectin was required for the multiplication of WSSV in red swamp crayfish (Procambarus clakii)

“…Hemocytes were collected as above and Immune-fluorescent assay was performed to determine the location of PcL-lectin in the hemocytes as described previously [15].…”

SUMO and SUMO-Conjugating Enzyme E2 UBC9 Are Involved in White Spot Syndrome Virus Infection in Fenneropenaeus chinensis

“…Small ubiquitin-like modifiers (SUMO) are a family of small proteins that could covalently attach to and detached from other proteins in cells to modify their functions. The process of covalent and reversible attaching of SUMO moiety to a target protein was known as SUMOylation, which was an important post-translational modification and involved in various cellular processes [ 1 – 3 ]. Although amino acid sequence of SUMO is similarly to ubiquitin, SUMOylation does not typically lead to degradation of the substrate and instead has a more diverse array of effects on substrate function, such as nuclear-cytosolic transport, transcriptional regulation, apoptosis, protein stability, response to stress and antiviral defense [ 4 , 5 ].…”