Interaction between WSSV envelope protein VP31 and triosephosphate isomerase in haemocytes of the Chinese shrimp, Fenneropenaeus chinensis (Osbeck, 1765) (Decapoda, Penaeoidea)

Abstract

To investigate the interaction between white spot syndrome virus (WSSV) envelope protein VP31 and haemocytes of the Chinese shrimp, Fenneropenaeus chinensis (Osbeck, 1765), the VP31 protein was recombinantly expressed in Escherichia coli (Migula, 1895) as a fusion protein with glutathione S-transferase tag (GST-tag). By Far Western Blotting, a prominent protein band of 26 kDa in haemocytes of F. chinensis was recognized by the recombinant VP31 (rVP31), which was identified as triosephosphate isomerase (TPI) by mass spectrometric analysis. Then, the TPI gene of F. chinensis was cloned and expressed as a fusion protein with thioredoxin/Histone/S-protein tag (Trx/His/S-tag) using the pET-32(a)+ vector, and the binding interaction between the recombinant TPI (rTPI) and rVP31 was further confirmed by pull-down assay. The expression of the TPI gene in haemocytes was significantly down-regulated in response to WSSV challenge. Moreover, the rTPI appeared to be able to partially block the WSSV infection and delay the death of infected shrimp in in vivo neutralization assay. These results indicate that TPI might play an important role in WSSV infection in F. chinensis.