atp6v0b gene regulates the immune response against Vibrio vulnificus in half-smooth tongue sole (Cynoglossus semilaevis)

The vacuolar ATPase (V-ATPase) plays an important role in phagocytic acidification, and its V0-V1 complex transports protons across the membrane to the phagocytic body. ATPase H+ transporting V0 subunit B (ATP6V0B) is a subunit of the V0 membrane integration domain of V-ATPase in mammals. At present, the role of the atp6v0b gene in teleost has not yet been defined. Here, we studied the role of atp6v0b gene in half-smooth tongue sole (Cynoglossus semilaevis) in response to Vibrio vulnificus infection. Liver ultrapathology data showed an increase in lysosomes and formation of autophagosome vesicles following an infection with Vibrio vulnificus, demonstrating binding of the lysosome to the autophagosome. The atp6v0b gene encodes 211 amino acids in the half-smooth tongue sole. The atp6v0b gene is constitutively expressed in all examined tissues of healthy half-smooth tongue sole, with the highest expression in blood and gill. A challenge test of the half-smooth tongue sole to different concentrations of Vibrio vulnificus was also done. The result showed that the relative upregulation of atp6v0b in liver, spleen, blood and heart with the highest expression in high infection group (group H) at 24h, which then decreased gradually as the reaction progressed to 72h. In contrast, muscle experienced the highest atp6v0b expression at 72h. Taken together, our data highlights the role of atp6v0b in regulating the immune response against Vibrio vulnificus.