engleski

Presence of Ecotoxicologically Relevant Pgp- and MRP- Transcripts and Proteins in Cyprinid Fish

One of the most intriguing defense strategies evolutionary developed in aquatic organisms is the activity of the multixenobiotic resistance (MXR) mechanism. Analogous to the multidrug resistance (MDR) phenomenon expressed in various mammalian tissues, it has been shown that ABC transport proteins are the key mediators of MXR activity. They provide resistance of aquatic organisms by binding xenobiotics and extruding them from cells in an energy-dependent manner. Since Cyprinid fish species are common target in freshwater biomonitoring programs, we have studied the presence of two main MDR/MXR efflux transporters: the P-glycoprotein (Pgp, Abcb1) and the MRP-like protein(s) (Abcc), in liver tissue from five Cyprinid fish species: common carp - Cyprinus carpio ; European chub - Sqalius cephalus ; sneep - Chondostroma nasus ; barbel – Barbus barbus ; and silver prussian carp – Carassius auratus gibelio. Their presence was evaluated on the mRNA and protein level. Various pairs of primers were designed to clone homologous fragments of MXR-related genes. Evaluation at the protein level was done by Western blotting using specific monoclonal antibodies raised against the human Pgp (Abcb1, Ab C219), MRP1 (Abcc1 ; Ab MRPm6) or MRP2 (Abcc2 ; Ab M2I-4). Transcripts of both key types of MXR transporters were identified in all species examined and here we provide the phylogenetic analysis for new partial sequences obtained. Immunochemical determinations with mammalian antibodies failed to identify the presence of MRP(s), but the Pgp expression was found in all five Cyprinid species. These results support the general idea about MXR as a defense system mediated by both Pgp and MRP types of ABC transport proteins.

aquatic organisms ; multixenobiotic resistance (MXR) ; ABC proteins ; Western blot analysis ; Phylogenetic analysis

nije evidentirano