Abstract:In this study, the apoptotic protein activator 1 (apoptotic protease activating factor-1, Apaf-1) gene of the swimming crab (Portunus trituberculatus) was cloned using the RACE technique. The full length of the gene was 2032 bp, and the ORF was 1050 bp, encoding 349 amino acids, with a predicted molecular weight of 39.13 kDa, and a theoretical isoelectric point of 7.67. The homology and phylogenetic analysis showed that the homology of Apaf-1 with Litopenaeus vannamei Apaf-1 was 51.27%, and it was also clustered with L. vannamei. Tissue expression analysis showed that the relative expression level of the Apaf-1 gene was highest in the hepatopancreas, followed by the muscle, heart, gill, and eyestalk, and was lowest in the hemocytes and epidermis. After different salinity stresses, the expression level of Apaf-1 in the stage Ⅱ juvenile crab reached its maximum at 3 h, and then decreased and then increased. Apaf-1 showed an upward trend in the gills after salinity 20 stress after 80 d, and an upward and downward trend in the hepatopancreas, suggesting that the change of salinity could affect the expression of Apaf-1 in the gill and hepatopancreas. The results showed that the expression of Apaf-1 reached its peak at 48 h after injection of Vibrio parahaemolyticus, which was 2.76 times higher than that of the control group (P<0.05), and increased 12 h after the injection of white spot syndrome virus (WSSV), which was 1.25 times higher than that of the control group (P<0.05). In the hepatopancreas, the expression of Apaf-1 reached its peak at 72 h after the injection of Vibrio parahaemolyticus, which was 5.44 times higher than that of the control group (P<0.05), and 12 h after the injection of WSSV. The peak value was 5.89 times higher than that of the control group (P<0.05), and the expression was up-regulated as a whole. This study provides a reference for further understanding the physiological function of the Apaf-1 gene in Portunus trituberculatus.
