Therole Of Myosin-9 Gene In Innate Immunity Of Scylla Paramamosain

Myosin-9 is an important component of myofibrillar filamentwhich is widely distributed in various tissues and organs of the body.In this research we studied the role of Scylla ParamamosainMyosin-9 gene in the immune process against White Spot Syndrome Virus(WSSV)or Vibrio alginolyticusinfection.Myosin-9 gene with a total length of 2735 bp,including ORF 2145 bp,encoding 715-aa-long protein was cloned from S.Paramamosain by Rapid Amplification of cDNA Ends(RACE).Amino acid sequence alignment and phylogenetic tree analysis showed that the gene was closely related to thatofPenaeus vannamei.The expression of Myosin-9 gene in muscle was the highest,followed by hemolymph,hepatopancreas,gill and digestive gland.Several known immune-related genes in the innate immune system were affected by the knock down of Myosin-9.Among them,the expression of c-type-lectin was significantly increased,Toll-like-receptorand crustin antimicrobial peptide genes were increased.The expression of JAK,STAT and prophenoloxidase were decreased significantly.Immune activity test showed that the total number of hemocytes decreased significantlyand the activity of phenoloxidase(PO)and superoxide dismutase(SOD)were decreased.The resultsindicated that Myosin-9 plays an important role in the immune system of S.Paramamosain.After WSSVinfection,the expression of Myosin-9 was significantly increased.After knock down ofMyosin-9,the phagocytosis rate of hemocytes was significantly reduced,the copy number of virus and the mortality rate of crabs were significantly increased compared with that of control.Myosin-9 may anticipatethe antiviral immune process of S.Paramamosain against WSSV infection.This study interpreted the role of Myosin-9 the antiviral immune process of S.Paramamosainand provided a theoretical basis for exploring the innate immunity of crustacean.After Vibrio alginolyticusinfection,the expression of Myosin-9 was up-regulated significantly.After knocking down ofMyosin-9,the phagocytosis rate of hemocytes was significantly reduced,the apoptosis rate of hemocytes was significantly increasedand the mortality rate of crabs was significantly increased.Thus the immune response of crab to V.alginolyticus was significantly reduced after knocking down Myosin-9.The results indicated that S.ParamamosainMyosin-9 may anticipate the immuneresponse to V.alginolyticus.This study revealed that Myosin-9 play an important role in the antimicrobial immune process of S.Paramamosain,and provides a theoretical basis for exploring the innate immunity mechanism of crustacean.This study demonstrates the importance of Myosin-9 in antidisease immunity of S.Paramamosain.Myosin-9 can be used as a target to screen green immune enhancechemicals that can improve the anti-disease immunity of craband provide strong support for the prevention and treatment of diseases in S.Paramamosain culture.