The Study Of β-1,3-glucan Recognition Protein 4 Precursor Response To BmNPV Infection And Functions In Innate Immunity In Bombyx Mori(L.)

BmNPV(Bombyx mori.Nucleopolyhedrovirus)is one of the most serious viruses in sericultural production.The molecular mechanisms of BmNPV infection and antiviral mechanisms of Bombyx mori are always the hotspots of this field for years.The research on the BmNPV infection and the antiviral mechanism of Bombyx mori is the main focus and hotspots in this field;however,the molecular mechanism is still not entirely clear.In this study,we identified the differentially expressed proteins,Bombyx mori β-1,3-glucan recognition protein 4 named BmβGRP4 from previous iTRAQ database.We analyzed differently expressed BmβGRP4 at transcriptional level and proteomic level in different larval tissues and different resistant silkworm strains(P50 and BC9)treated and control group,to elucidate the role of BmβGRP4 in BmNPV infection and the function of BmβGRP4 in microbe-induced immune related signal pathways.The results are listed as follow:1.Identification of differentially expressed BmβGRP4 and response to differently expressed validation of infection NPVBased on iTRAQ database,we identified the differentially expressed protein,Bombyx mori β-1,3-glucan recognition protein 4 named BmβGRP4,and bioinformatic analysis of BmβGRP4 were performed.We verified the iTRAQ results using reverse transcription quantitative PCR(RT-q PCR)and macth the results.Western blotting results indicated that the proteomic level of BmβGRP4 in different tissues was up-regulated in P50+ compared to P50-and was down-regulated in BC9+ compared to BC9-.2.Analysis of BmβGRP4 expression level at transcriptional level and proteomic levelRT-qPCR analysis showed that the transcriptional level of BmβGRP4 was the higher in the midgut and malpighian tubules than other tissues.Western blotting analysis showed that the proteomic level of BmβGRP4 was the higher in the midgut and hemolymph than other tissues.Immunofluorescence analysis was performed to check the distribution of BmβGRP4 protein in the midgut and fat body.The results of immunofluorescence showed that BmβGRP4 protein is distributed in the midgut and fat body.3.The effect of virus genes proliferation after blocking the BmβGRP4The results further verified that injection of anti-BmβGRP4 serum could inhibit BmNPV proliferation in B.mori.It is suggested that BmβGRP4 may be involved in BmNPV infection.4.The function of BmβGRP4 in microbe-induced immune related signal pathwaysThe recombinant BmβGRP4 protein was found that can inhibit prophenoloxidase activation,but did not affect phenoloxidase activity in B.mori hemolymph.These results suggested that BmβGRP4 can inhibit the activation of Toll and IMD signal pathways,but it had not obvious influence the JAK/STAT signal pathways.