title: A keratin 18 transgenic zebrafish Tg(k18(2.9):RFP) treated with inorganic arsenite reveals visible overproliferation of epithelial cells.
abstract: Inorganic arsenic has strong human carcinogenic potential, but the availability of an animal model to study toxicity is extremely limited. Here, we used the transgenic zebrafish line Tg(k18(2.9):RFP) as an animal model to study arsenite toxicity. This line was chosen because the red fluorescent protein (RFP) is expressed in stratified epithelia (including skin), due to the RFP reporter driven by the promoter of the zebrafish keratin 18 gene. We titrated doses of inorganic arsenite for zebrafish embryos and found that arsenite exposure at 50 microM for 120 h was suitable for mimicking a long-term, chronic effect. When embryos derived from Tg(k18(2.9):RFP) adults were treated with this arsenite dose and time of exposure, abnormal phenotypes were not noticeable under the light microscope. However, arsenic keratosis was visible in the epithelial cells under the fluorescent microscope. Morphological defects became more severe with increased dose and exposure duration, suggesting that the severity of skin lesions was dose- and time-dependent. Histochemical examination of keratosis after 4',6'-diamidino-2-phenylindole hydrochloride (DAPI) staining showed that the epithelial cells overproliferated after treatment with arsenite. Therefore, this Tg(k18(2.9):RFP) zebrafish line is an excellent model for studying toxicity induced by inorganic arsenite and may have potential for studying other environmental pollutants.
authors.affiliation: Institute of Molecular and Cellular Biology, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Yun-Hsin
authors.initials: YH
authors.lastname: Wang
authors.forename: Yau-Hung
authors.initials: YH
authors.lastname: Chen
authors.forename: Tai-Na
authors.initials: TN
authors.lastname: Wu
authors.forename: Yu-Ju
authors.initials: YJ
authors.lastname: Lin
authors.forename: Huai-Jen
authors.initials: HJ
authors.lastname: Tsai
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D018053:Arsenites / Q000633:toxicity*; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D053538:Keratin-18; D007633:Keratins / Q000235:genetics*; D007642:Keratosis / Q000139:chemically induced* / Q000473:pathology; D016014:Linear Models; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D008856:Microscopy, Fluorescence; D023421:Models, Animal; D011401:Promoter Regions, Genetic; D011897:Random Allocation; D012867:Skin / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D013723:Teratogens / Q000633:toxicity*; D018675:Toxicity Tests / Q000379:methods; D015027:Zebrafish / Q000196:embryology / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics*; D000097573:Red Fluorescent Protein
chemical_list: D018053:Arsenites; D053538:Keratin-18; D007633:Keratins; D008164:Luminescent Proteins; D013723:Teratogens; D029961:Zebrafish Proteins; D000097573:Red Fluorescent Protein; C479873:krt18a.1 protein, zebrafish; C015001:arsenite