Molecular Evolution of P-glycoproteins (P-gp) in Teleost Fishes

Multixenobiotic resistance (MXR) in aquatic organisms exposed to natural toxins or anthropogenic contaminants is a phenomenon analogous to multidrug resistance (MDR) in mammalian tumor cell lines tolerant of anti-cancer drugs. Multidrug resistance is commonly due to the elevated expression of transmembrane P-gps which actively transport a wide variety of structurally and functionally diverse compounds. The effect of xenobiotic exposures on P-gp activity and protein titer has been examined in wild and captive populations of aquatic invertebrates and vertebrates. Molecular evolution of P-gp was investigated in teleost fishes, which exhibit remarkable diversity in morphology, behavior, and adaptations. Several phylogenetic analysis were performed using all teleosts P-gp amino acid and complementary DNA (cDNA) sequences present in GenBank. P-gp molecular evolution in teleosts seemed to follow identical evolution pathways to teleost fishes speciation.