Fang He and Jimmy Kwang, in an article in Virology Journal 2008, state that WSSV ORF403 is predicted to encode a protein of 641 amino acids, which contains a C3H2C2 RING structure.
In the presence of an E2 conjugating enzyme from shrimp, WSSV403 can ubiquitinate itself in vitro, indicating it can function as a viral E3 ligase. Besides, WSSV403 E3 ligase can be activated by a series of E2 variants.
Based on RT-PCR and Real time PCR, we detected transcription of WSSV403 in the commercial specific-pathogen-free (SPF) shrimp, suggesting its role as a latency-associated gene. Identified in yeast two-hybrid screening and verified by pull-down assays, WSSV403 is able to bind to a shrimp protein phosphatase (PPs), which was characterized before as an interaction partner for another latent protein WSSV427.
New Research into White Spot Syndrome
GLOBAL - White spot syndrome virus (WSSV) is one major pathogen in shrimp aquaculture and a study by Fang He and Jimmy Kwang suggest that WSSV403 is a regulator of latency state of WSSV by virtue of its E3 ligase function.