title: Functional characterization of P-glycoprotein in the intertidal copepod Tigriopus japonicus and its potential role in remediating metal pollution.
abstract: The intertidal copepod Tigriopus japonicus has been widely used in aquatic toxicity testing for diverse environmental pollutants including metals. Despite relatively well-characterized in vivo physiological modulations in response to aquatic pollutants, the molecular mechanisms due to toxicity and detoxification are still unclear. To better understand the mechanisms of metal transport and further detoxification, T. japonicus P-glycoprotein (TJ-P-gp) with conserved motifs/domains was cloned and measured for protein activity against the transcript and protein expression profiles in response to metal exposure. Specifically, we characterized the preliminary efflux activity and membrane topology of TJ-P-gp protein that supports a transport function for chemicals. To uncover whether the efflux activity of TJ-P-gp protein would be modulated by metal treatment, copepods were exposed to three metals (Cd, Cu, and Zn), and were observed for both dose- and time-dependency on the efflux activity of TJ-P-gp protein with or without 10μM of P-gp-specific inhibitors verapamil and zosuquidar (LY335979) for 24h over a wide range of metal concentrations. In particular, treatment with zosuquidar induced metal accumulation in the inner body of T. japonicus. In addition, three metals significantly induced the transporting activity of TJ-P-gp in a concentration-dependent manner in both transcript and protein levels within 24h. Together these data indicate that T. japonicus has a conserved P-gp-mediated metal defense system through the induction of transcriptional up-regulation of TJ-P-gp gene and TJ-P-gp protein activity. This finding provides further understanding of the molecular defense mechanisms involved in P-glycoprotein-mediated metal detoxification in copepods.
authors.affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Chang-Bum
authors.initials: CB
authors.lastname: Jeong
authors.affiliation: Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea.
authors.forename: Bo-Mi
authors.initials: BM
authors.lastname: Kim
authors.affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Rae-Kwon
authors.initials: RK
authors.lastname: Kim
authors.affiliation: Department of Marine Resource Development, College of Life Sciences, Gangneung-Wonju National University, Gangneung 210-702, South Korea.
authors.forename: Heum Gi
authors.initials: HG
authors.lastname: Park
authors.affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Su-Jae
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Department of Marine Sciences and Convergent Technology, College of Science and Technology, Hanyang University, Ansan 426-791, South Korea.
authors.forename: Kyung-Hoon
authors.initials: KH
authors.lastname: Shin
authors.affiliation: School of Biological Sciences and the Swire Institute of Marine Science, The University of Hong Kong, Poklam Road, Hong Kong, China.
authors.forename: Kenneth Mei Yee
authors.initials: KM
authors.lastname: Leung
authors.affiliation: Department of Marine Science, College of Natural Sciences, Incheon National University, Incheon 406-772, South Korea. Electronic address: jsrhee@incheon.ac.kr.
authors.forename: Jae-Sung
authors.initials: JS
authors.lastname: Rhee
authors.affiliation: Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea. Electronic address: jslee2@skku.edu.
authors.forename: Jae-Seong
authors.initials: JS
authors.lastname: Lee
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis* / Q000378:metabolism*; D000818:Animals; D033342:Copepoda / Q000737:chemistry* / Q000235:genetics; D005786:Gene Expression Regulation; D008658:Inactivation, Metabolic / Q000235:genetics; D008670:Metals / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D015854:Up-Regulation; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D008670:Metals; D014874:Water Pollutants, Chemical
keywords: Copepod; Metal; P-glycoprotein; Pollution; Tigriopus japonicus