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WSSV (White Spot Syndromic Virus, WSSV), is a serious hazard to the main pathogen of the shrimp farming industry. The papers from both pathogen and host start focused on WSSV virus membrane protein VP466 shrimp vivo protein Rab, the complex formed between tropomyosin (tropomyosin) and actin (actin) (complex) played an important role in shrimp immune and viral infection, not only to find the virus membrane protein receptors in the host body to provide a theoretical basis but also provide a scientific basis for the establishment of effective prevention and treatment methods. The thesis proved VP466-Rab-tropomyosin-actin is a composite body. According to the results of the GST-pulldown, mass spectrometry, found that the Rab proteins WSSV membrane protein VP466, actin (actin), interaction between tropomyosin (tropomyosin). By co-transfection of insect cells, co-immunoprecipitation, Western analysis and other methods, in vivo and in vitro have proved the existence of interactions between the virus membrane protein VP466 and Rab, tropomyosin, and actin, and further validate the VP466 and Rab The interaction of the tropomyosin protein fragment, found VP466 the C-terminal can be used with both Rab proteins with tropomyosin protein interaction, and are in the same region. Followed VP466-Rab-tropomyosin-actin complex function research. First, VP466 protein through the binding between Rab protein and actin, have an important role in the immune response of the host itself. RNAi inhibition of Rab gene expression, phagocytic activity weakened, the increase in the number of viral copies; injection of mRNA in vitro Rab gene upregulation results phagocytic activity increased, the decline in the number of viral copies. Vitro and in vivo tests proved, VP466 protein can promote increased Rab GTPase enzyme activities. Therefore, the host immune response to the virus a possible way, Rab proteins within cells recognize viral membrane protein VP466, with its combination of enzyme activity increased after allosteric promote actin to favor the opposite direction swallowed occurred, thereby increasing blood phagocytic virus ability to cause the reduction of the number of viral copies. Second, VP466 protein through the binding between tropomyosin and actin conducive to infection of the virus itself. Real-time PCR analysis showed that the copy number of the virus is declining, illustrates the the VP466 protein in the the WSSV virus infection process plays an important role in suppression VP466 gene expression using RNAi. Using RNAi inhibition of tropomyosin gene expression by Real-timePCR, semi-quantitative PCR analysis of viral copy number of the virus is found to decrease. Therefore, the virus infection in a possible ways between the viral membrane protein VP466 and cytoskeletal protein tropomyosin protein and actin binding, through the movement of the cytoskeletal protein, is conducive to infection of the virus itself. Third, by deletion mutation discovered VP466 Rab and tropomyosin binding sites in the same structural region, suggesting that the combination thereof is a competitive relationship, this competition will affect the the VP466 with tropomyosin binding promoting the infection of the virus itself promote the host immune response, or combined with Rab. In conclusion, our results for the first time found a the WSSV virus membrane protein VP466 is a bifunctional protein, host of different protein binding, may play a role in the host immune or viral infection.
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