Molecular analysis and heavy metal detoxification of ABCC1/MRP1 in zebrafish

Abstract

ABCC1/MRP1 belongs to the ATP-binding cassette superfamily and its elevated expression is closely associated with the multidrug resistance of various tumor cells. In normal tissues, ABCC1 confers resistance to a wide variety of xenobiotics and toxicants, demonstrating its important roles in tissue defense. Here, we report the cloning and functional characterization of abcc1 gene in zebrafish. This gene is localized on zebrafish chromosome 3 and contains a 4,557 bp open-reading frame. The deduced polypeptide is composed of 1,518 amino acids, which shares 70% identity with human ABCC1. Phylogenetic analysis revealed that ABCC1 proteins from thirteen vertebrate species are highly conserved during evolution. Transcriptional expression of zebrafish abcc1 gene in developing embryos was examined by whole-mount in situ hybridization and real-time PCR. Transcripts of zebrafish abcc1 gene were detectable in four-cell stage embryos, indicating that this gene is maternally expressed. ABCC1 mRNAs were ubiquitously distributed in embryos before 12 h post-fertilization (hpf) and mainly localized in eyes and brain from 24 to 72 hpf, and in gills from 96 to 120 hpf. In addition, zebrafish abcc1 gene was highly expressed in 1-hpf embryos and detected in all adult tissues examined, with highest expression in testis and lowest in heart and liver. Exposure of ZF4 cells and embryos to CdCl 2 Á2.5H 2 O, HgCl 2 , Pb(NO 3 ) 2 , or Na 3 AsO 4 Á12H 2 O significantly induced transcriptional expression of abcc1 gene. Furthermore, overexpression of abcc1 improved the survival rates of embryos exposed to Cd, Hg or As, while overexpression of a abcc1 mutant (ABCC1-G1420D) sensitized zebrafish embryos to toxic metals. These data indicate that zebrafish ABCC1 has crucial roles in heavy metals detoxification.

Zebrafish Abcb4 is a potential efflux transporter of microcystin-LR

“…So far, functions of MRP subfamily proteins in aquatic organisms are well characterized. Our previous studies have revealed that zebrafish Abcc1 (Long et al, 2011a), Abcc2 (Long et al, 2011d) and Abcc5 (Long et al, 2011b) play vital roles in efficient detoxification of heavy metals. Zebrafish Abcb4 has been demonstrated to function as a cellular toxicant transporter, which can extrude a variety of toxic compounds including galaxolide, tonalide and phenanthrene (Fischer et al, 2013), so it may play an important role in cellular protection against xenobiotics.…”

“…Collection of eggs and culture of embryos were performed as in our previous study (Long et al, 2011a;Gu et al, 2013). Embryos were staged according to hour post-fertilization (hpf).…”

Monomethylarsenic Diglutathione Transport by the Human Multidrug Resistance Protein 1 (MRP1/ABCC1)

“…The ubiquitous nature of arsenic in the environment has led to the evolution of arsenic adaptation mechanisms from bacteria to humans (Rosen and Liu, 2009). Members of the ABC transporter superfamily subfamily "C" have been shown to be critical for protecting many organisms from arsenic, including Saccharomyces cerevisiae, Leishmania, Arabidopsis, Caenorhabditis elegans, and Danio rerio (Broeks et al, 1996;Dey et al, 1996;Ghosh et al, 1999;Long et al, 2011;Song et al, 2010). In all of these organisms, ABCC proteins detoxify arsenic either by extrusion from cells or through sequestration within intracellular organelles as thiol conjugates.…”

Molecular characterization and functions of zebrafish ABCC2 in cellular efflux of heavy metals

“…The tagged zebrafish abcc2 was then subcloned into the pRc/CMV2 expression vector at the HindIII and XbaI sites to generate the pRc/CMV2-ABCC2-Flag. The pRc/CMV2-EGFP generated in our previous study (Long et al, 2010a) was used as a control in functional characterization of zebrafish ABCC2.…”

“…However, most of MRP transporters in zebrafish are yet to be characterized and little is known about their physiological functions in development and detoxification of toxicants including toxic heavy metals. In our previous studies, we demonstrated the potential functions of zebrafish ABCC1 and ABCC5 in heavy metal detoxification (Long et al, 2010a;Long et al, 2011), and found that the up-regulation of zebrafish ABCC2 may be involved in the heavy metal resistance of ZF4-Cd cells selected by chronic cadmium exposure (Long et al, 2010b). In this study, we cloned the abcc2 cDNA from zebrafish, investigated its developmental and tissue-specific expression, transcriptional responses to heavy metals, and evaluated its roles in cellular efflux of heavy metals such as cadmium, mercury and lead.…”