Molecular analysis, developmental function and heavy metal-induced expression of ABCC5 in zebrafish

Comp Biochem Physiol B Biochem Mol Biol. 2011 Jan;158(1):46-55. doi: 10.1016/j.cbpb.2010.09.005. Epub 2010 Sep 22.

Abstract

ABCC5/MRP5 is an organic anion transporter that participates in tissue defense and cellular signal transduction through efflux of anticancer drugs, toxicants and a second messenger cGMP, but its physiological functions in zebrafish remain to be defined. Herein, we report the characterization, spatiotemporal expression and developmental function of zebrafish ABCC5 and its transcriptional responses to heavy metals. Zebrafish abcc5 gene is located on chromosome 18 and comprised of 28 exons. The deduced polypeptide of zebrafish ABCC5 consists of 1426 amino acids, which shares high sequence identity with those from other species. Zebrafish abcc5 is maternally expressed and its transcripts are mainly distributed in brain, lens, liver and intestine of developing embryos. In adults, zebrafish abcc5 is extensively expressed, at higher levels in testis, brain, eye, ovary, intestine and kidney, but at relatively lower levels in gill, liver, heart and muscle. Blockage of endogenous ABCC5 activity by its dominant-negative led to the developmental retardation of zebrafish embryos in which activity of p21 signaling was markedly stimulated and cellular cGMP content was significantly increased. In addition, expression of abcc5 in ZF4 cells and zebrafish embryos was significantly induced by cadmium (Cd), lead (Pb), mercury (Hg) or arsenic (As). The induced expression of ABCC5 by heavy metals was mainly detected in the liver of embryos at 96-h post-fertilization (hpf). In adult zebrafish, expression of abcc5 in brain, intestine, liver, kidney and ovary was significantly induced by one or more of these heavy metals. Furthermore, overexpression of ABCC5 attenuated the toxicity of Cd to zebrafish embryos, but did not affect the toxicity of Hg or As. Thus, ABCC5 is likely to play an active role in embryonic development and heavy metal detoxification through the export of second messenger molecules and toxicants out of cells in zebrafish.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Embryonic Development / drug effects*
  • Embryonic Development / genetics
  • Gene Expression Regulation, Developmental / drug effects
  • Gene Expression Regulation, Developmental / genetics
  • Metals, Heavy / pharmacology*
  • Multidrug Resistance-Associated Proteins* / chemistry
  • Multidrug Resistance-Associated Proteins* / genetics
  • Multidrug Resistance-Associated Proteins* / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Zebrafish
  • Zebrafish Proteins* / chemistry
  • Zebrafish Proteins* / genetics
  • Zebrafish Proteins* / metabolism

Substances

  • ABCC5 protein, zebrafish
  • Metals, Heavy
  • Multidrug Resistance-Associated Proteins
  • Zebrafish Proteins