Mechanism Of PcLecG And C1qR Involved In Anti-WSSV Immune Response In Procambarus Clarkii

The crayfish(Procambarus clarkii)is an important freshwater aquaculture species in China.White spot syndrome virus(WSSV)is characterized by rapid transmission and high lethality,and white spot disease has caused great losses to the crayfish aquaculture industry.The epidemiological investigation of WSSV in different batches of egg-holding shrimp revealed that vertical transmission may not be the main cause of WSSV carriage in the offspring of crayfish.The immune system is an important barrier of the organism,which is able to recognize pathogenic molecules and regulate the corresponding immune response of the organism.C-type lectins play an important role in the innate immune response.It is generally believed that the classical complement system emerged after chordates,and the origin of the pathogen recognition mechanism of the complement system remains to be further revealed.In this study,a lectin Pc Lec G containing a C1q-like motif was identified from crayfish,and it was found that it was constitutively distributed in various tissues and responded to WSSV stimulation,and that in vivo injection of Pc Lec G protein was effective in inhibiting the replication level of WSSV.Further analysis revealed that C1 q R localized on the cell membrane was able to bind the major vesicle protein of WSSV,thus recruiting Pc Lec G by binding to the C1q-like region of Pc Lec G.The activation of Pc Lec G and C1 q R homonuclear transcription factor Dorsal and its entry into the nucleus were found to be closely related by techniques such as Western blot and immunocytochemistry.The activation of Dorsal by Pc Lec G and C1 q R was diminished after in vivo interference with SRPK,indicating that the activation of Dorsal by Pc Lec G and C1 q R was dependent on SRPK.Further studies revealed that the Pc Lec G-C1 q R-SRPK-Dorsal axis could regulate the expression of the antiviral protein Pc LT,thereby inhibiting WSSV infection and replication.This study clarifies that vertical transmission is not the main cause of WSSV carriage in the offspring of crayfish.We also elucidated that Pc Lec G in crayfish recognizes WSSV and activates Dorsal in a similar way to pathogen recognition by the complement system,and participates in the antiviral immune response.This study not only provides some reference for WSSV-free pathogen selection in crayfish and enriches the innate immune knowledge system,but also provides some theoretical basis for the prevention and control of white spot syndrome in crayfish.