Expression Analysis Of Four Genes Of Bostrychus Sinensis Caspase Family Under The Stress Of Vibrio Parahaemolyticus And Poly(I:C)

Apoptosis is an active,highly ordered and gene determined process that automatically terminate cell life.It plays an important role in ensuring the healthy development of multicellular organisms.It plays a key role in the evolution of organisms,maintaining the stability of the intracellular environment and maintaining the number of cells in tissues.In the field of biological immunology,the process of apoptosis involves the same series of protein families.Among them,cysteine aspartic acid specific protease(caspases)is a protease system that can directly trigger the disintegration of apoptosis,and plays an important role in the process of apoptosis.In this study,we mainly consider the sequence identification,evolutionary analysis and expression analysis of four caspases Bscasp-1,Bscasp-7,Bscasp-8 and Bscasp-9,from Bostrychus sinensis.Among them,the Bscasp-1,Bscasp-7,Bscasp-8 and Bscasp-9 gene protein sequences encode 390 bp,314bp,478 bp and 435 bp amino acids,respectively.Bscasp-1 and Bscasp-9 genes contain three conserved domains including a CARD domain,a CASc domain,in which the CASc domain contains a P20 large subunit domain and a P10 small subunit domain.Bscasp-8 gene encodes two death effect domains(DED-1,DED-2),a large subunit p20 and a small subunit p10.There is only one CASc domain in Bscasp-7 gene.A cysteine active site(Cys)and a conserved pentapeptide sequence QACRG were found in P20 domain of Bscasp-1 gene.Bscasp-7 gene contains a histidine active site(his),a cysteine active site and a conserved pentapeptide sequence.QACRG.Bscasp-8 gene has a cysteine active site and a conserved pentapeptide sequence.QACQG.Bscasp-9 contained a cysteine active sequence and a histidine active sequence and has a conserved pentapeptide sequence.QACGG.Using RT-PCR technology to test the expression of Bscasp-1,Bscasp-7,Bscasp-8 and Bscasp-9 genes in ten tissues,and the changes of expression levels of Bscasp-1,Bscasp-7,Bscasp-8 and Bscasp-9 genes after Vibrio parahaemolyticus infection and stimulation of poly(I:C).It is speculated that caspase-1,caspase-7,caspase-8 and caspase-9 genes play an important role in the anti-bacterial immunity of Bostrychus sinensis.The results showed that the Bscasp-1,Bscasp-7,Bscasp-8 and Bscasp-9 genes were widely expressed in ten normal tissues.Among them,the expression of Bscasp-1,Bscasp-7 and Bscasp-8 genes in the gill was the highest,and the expression of Bscasp-9 gene in liver was the highest.After Vibrio parahaemolyticus infection,the genes of Bscasp-1,Bscasp-7,Bscasp-8 and Bscasp-9 were significantly up-regulated.The expression peaks of Bscasp-1 and Bscasp-7 genes in the peripheral blood were 86-fold and 161-fold that of the control.The peak expression of Bscasp-8 gene in spleen was 281-fold that in normal control group.The peak expression of Bscasp-9 gene in the peripheral blood was only 8-fold higher than that in the control group.After poly(I:C)stimulation,the change of Bscasp-1 and Bscasp-7 expression in the headkidney were the most obvious;peak expression were about 81-fold and 255-fold more than that of the control.In addition,the expression of Bscasp-8 and Bscasp-9 in the peripheral blood and liver was 168-fold and 18-fold higher than that in the control group,respectively.The results of this study indicated that caspase-1,caspase-7,caspase-8 and caspase-9 genes may be involved in the immune response induced by bacteria and viruses in Bostrychus sinensis,and proved for the first time that caspase-1,caspase-7,caspase-8 and caspase-9 genes are crucial for the optimal defense against bacterial infection or viral stimulation in Bostrychus sinensis.