Transcription and identification of a novel envelope protein (VP124) gene of shrimp white spot syndrome virus

White spot syndrome virus (WSSV) is one of the most virulent pathogens in shrimp culture worldwide. Combining SDS-PAGE with mass spectrometry, a novel envelope protein from WSSV was identified to match an open reading frame (ORF) of WSSV genome. This ORF contained 3582 nt, encoding 1194 aa, and was termed the vp124 gene. One part of the whole gene (named vp124p) was cloned into pET-GST vector and expressed as a fusion protein with glutathione S-transferase (GST) in Escherichia coli strain BL21 (DE3). Specific antibodies were raised using the purified fusion protein (GST-VP124P). Temporal transcription analysis revealed that the vp124 gene was a late gene. Western blot analysis showed that the mouse anti-GST-VP124P antibodies reacted specifically with VP124 present either in the WSSV virions or in the viral envelopes, and did not react with the proteins of the viral nucleocapsids. VP124 was located in the WSSV virions as an envelope protein using immunoelectron microscopy.