Molecular Characterization Of Cytokine Receptor Domeless And Its Functional Research On WSSV Infection Of Cherax Quadricarinatus

White spot syndrome virus(WSSV)is a primary menace of global shrimp cultivation,up to now there is no effective method to absolutely crue this disease.At present,the main preventive measure is to improve shrimpinnate immune response,cytokines and cytokine receptors are important factors involved in innate immune response.Our research taken red claw crayfish as model animals of WSSV infection,aimed to explore the relationship between WSSV and host cytokine receptor as well as downstream JAK/STAT signaling pathway,and provide new sight to prevent and cure WSSV disease.In this research we firstly obtained three ORF sequences of JAK/STAT signaling pathway components in red claw crayfish,including cytokine receptor Domless,JAK kinase and STAT transcription factor(named as CqDome,CqJAK and CqSTAT,respectively).The CqDome contained extracellular conservative structure domains of CBM and FN3,hydrophobic transmembrane region and intracellular region.Phylogenetic analysis indicated that CqDome shared high homology with crustaceans like crab and shrimp.Tissues distribution showed that CqDome generally expressed in all the tissues tested with a highly expression in hemocyte."pGEX-CBM" recombinant plasmid was constructed and expressed with a GST-tag in E.coli prokaryotic expression system,the fusion protein with high purity(about 95%)was purified.Knocked down of CqDome with RNAi in haematopoietic tissue(Hpt)cells resulted in significantly downregulation of WSSV immediate early gene IE1 and envelope protein gene VP28 expression,the protein expression of VP28 was also reduced,illustrated that the replication of WSSV was inhibited.In addition,the transcription of CqJAK and CqSTAT decreased significantly after gene silence of CqDome,and CqJAK expression recovered subsequently demonstrated that CqDome can positively regulate CqJAK and CqSTAT.Further research showed that the phosphorylation levelof CqSTAT enhanced post WSSV infection,and loss-of-function of CqDome significantly reduced CqSTAT phosphorylation,indicated that CqDome participates in signal transmission of JAK/STAT pathway,and phosphorylated CqSTAT was beneficial to WSSV gene expression.We revealed the molecular mechanism of CqDome to participate in signal transmission of JAK/STAT pathway,and clarified the mechanism that CqDome influenced WSSV infection to further reveal the pathogenesis of WSSV and improve the antiviral immunity of shrimp.