Cystic fibrosis transmembrane conductance regulator in the gills of the climbing perch, Anabas testudineus, is involved in both hypoosmotic regulation during seawater acclimation and active ammonia excretion during ammonia exposure

摘要: This study aimed to clone and sequence the cystic fibrosis transmembrane conductance regulator (cftr) from, determine effects of seawater acclimation or exposure 100 mmol l−1 NH4Cl in freshwater on its mRNA protein expressions in, gills Anabas testudineus. There were 4,530 bp coding for 1,510 amino acids cftr cDNA from A. The branchial expression fish kept was low (<50 copies transcript per ng cDNA), but significant increases observed acclimated 1 day (92-fold) 6 days (219-fold). Branchial Cftr detected not control, indicating that Cl− excretion through apical epithelium essential acclimation. More importantly, exposed ammonia also exhibited a increase (12-fold) cftr, with being expressed type Na+/K+-ATPase-immunoreactive cells apparently different involved It is probable generated favorable electrical potential across membrane drive \( {\text{NH}}_{4}^{ + } \) against concentration gradient yet be determined transporter, it led slight loss endogenous Cl−. Since resulted decreases blood pH, [HCO3−] [total CO2] testudineus, can deduced active could driven by exit HCO3− Cftr. Furthermore, testudineus uniquely responded increasing ambient pH decreasing bafilomycin-sensitive V-type H+-ATPase activity, which suggests might have NH3 permeability.