Researches On The Interaction Sites Between The Envelope Protein VP26and Nucleocapsid Protein VP51of White Spot Syndrome Virus And The Method Of Preserving WSSV At Low Temperature

White spot syndrome virus (WSSV) is a large, rod-shaped, envelopeddouble-strand DNA virus which is the major pathogen causing the increasing dead ofthe cultured penaeid shrimp. The main struture of WSSV had been identified since1990s. In this study, we try to not only identify the interaction sites between theenvelope protein VP26and nucleocapsid protein VP51but develope a simple methodof preserving WSSV.(1) The interaction between envelope protein VP26and nucleocapsid proteinVP51had been demonstrated, which is the key factor for the envelopment of WSSVvirion. To further study the interaction between VP26and VP51, we had identified theinteraction sites of the two proteins by using Co-Immunoprecipitation. During theresearch, a series of recombinant V5-tagged proteins of VP51protein and severalrecombinant HIS-tagged proteins of VP26protein were constructed. After that, one ofrecombinant proteins of VP51and one recombinant proteins of VP26werecoexpressed in E.coil BL21then the interaction of the two proteins were identified byusing the Co-Immunoprecipitation.We found that two central fragments (residues141–180, residues261-350) andthe C-terminal fragment (residues431-466) of VP51were the core regions thatinteracted with VP26. Meanwhile, the C-terminal region (residues156–204) of VP26was the main fregment that could interact with not only the two central fregments ofVP51but also the C-terminal fragment of VP51.(2) During the research, we found that it was a common phenomenon that notonly the purified WSSV virions stored at4℃began degration within several days butalso the infectivity of WSSV suspension purified at different time might vary. Toaddress the problems, we tried to preserve WSSV at low temperature. Firstly, a seriesof different concentrations of DMSO or glycerol were added into the WSSVsuspension as the preservative, then these mixtures were stored at-80℃. Aftercryopreservation for15days, WSSV virions were characterized by using TEM. Compared with the negative group containing no any preservative, the number ofintact WSSV virions in the mixture containing any concentration of DMSO wasextraordinary greater, while the acceptable concentration of DMSO was10%(v/v). Asa contrast, the glycerol did not conctribute to preserve the intact virions effectively.The real-time PCR results showed that there was no great difference of infectivitybetween the mixture containing10%DMSO stroed for15days and that stored for30days.