Gene expression analysis of the ABC efflux transporters in rainbow trout (Oncorhynchus mykiss)

Transcriptional expression analysis of ABC efflux transporters and xenobiotic-metabolizing enzymes in the Chinese rare minnow

“…Through binding and hydrolyzing ATP, these proteins actively transport various structurally unrelated compounds across the cell membrane and act as efflux pumps for various chemicals, environmental toxicants, and their metabolites. In humans, 49 ABC genes organized into seven subfamilies (A-G) have been described (Dean and Annilo, 2005;Lončar et al, 2010). Despite the large number of ABC proteins, previous studies have revealed that the P-glycoprotein (ABCB1), the Bile Salt Export Pump (BSEP; ABCB11), the multidrug resistanceassociated proteins 1-5 (ABCC1-5), and the breast cancer resistance protein (ABCG2) are the most toxicologically relevant proteins in mammals (Leslie et al, 2005;Szakacs et al, 2008).…”

“…Several members of the ABC transporter family confer multixenobiotic resistance (MXR) in aquatic organisms (Epel, 1998;Bard, 2000). The identification of these transporters and their putative role in the defense against natural and man-made substances has been investigated in more than 40 aquatic species (e.g., rainbow trout) (Lončar et al, 2010). In addition, a number of these ABC genes have been identified and studied in several fish species including zebrafish (Long et al, 2011), Nile tilapia (Costa et al, 2012), killifish (Christine Paetzold et al, 2009), and Antarctic fish (Zucchi et al, 2010).…”

“…Previous studies have determined the tissue expression patterns of ABCC2 in zebrafish (Long et al, 2011) and little skate (Cai et al, 2003), and ABCB1 in the sheepshead minnow (Hemmer et al, 1998). Only a few studies have assessed the expression profiles of other toxicologically relevant ABC transporters in fish, e.g., ABCB11 and ABCG2 (Lončar et al, 2010;Costa et al, 2012). Therefore, more information about the distribution patterns of these ABC transporters in fish is needed to characterize their roles in the different tissues of fish.…”

“…In addition, an increase in the ABCB1 mRNA level was observed in Antarctic fish exposed to Cd (Zucchi et al, 2010). Nevertheless, the regulation and function of these ABC transporters in fish are still relatively unclear (Lončar et al, 2010;Long et al, 2011;Costa et al, 2012). The induction of the phase I (e.g., CYP1A) and phase II (e.g., GSTs, GCLG, and UGTs) xenobiotic-metabolizing enzyme genes by environmental pollutants (e.g., PAHs) has been widely studied (Van der Oost et al, 2003).…”

“…Despite the physiological importance of the toxicologically relevant ABC transporters and their role in cellular defense, their expression patterns, mechanisms of regulation and biological functions have not been fully characterized in fish (Lončar et al, 2010;Long et al, 2011;Costa et al, 2012). Therefore, the aims of the present study were to identify five toxicologically relevant ABC transporter genes in rare minnow, characterize their basal expression patterns across eight different tissues (liver, gill, intestine, kidney, spleen, brain, skin, and muscle), and assess the transcriptional effects of pyrene exposure on these ABC genes as well as several xenobioticmetabolizing enzyme genes in the liver of the Chinese rare minnow.…”