title: Transcriptomic characterization of zebrafish larvae in response to mercury exposure.
abstract: Mercury is a widespread toxicant in aquatic environment that can cause deleterious effects on fish. Although a number of mercury-regulated genes have been investigated in adult fish, the transcriptional responses of fish larvae to acute mercury exposure are not well understood. In this study, RNA sequencing was used to examine the transcriptional changes in developing zebrafish larvae under a low concentration of mercuric chloride exposure from 24 to 120hpf. Our initial results showed that a total of 142.59 million raw reads were obtained from sequencing libraries and about 86% of the processed reads were mapped to the reference genome of zebrafish. Differential expression analysis identified 391 up- and 87 down-regulated genes. Gene ontology enrichment analysis revealed that most of the differential expressed genes are closely related to the regulation of cellular process, metabolic process, multicellular organismal process, biological regulation, pigmentation, and response to stimulus. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis demonstrated that antigen processing and presentation was the most significantly enriched pathway. Moreover, we characterized a novel and sensitive mercury-induced ABCB (ATP- binding cassette B subfamily) transporter gene - abcb5. This gene is localized on zebrafish chromosome 16 and contains a 4014bp open-reading frame. The deduced polypeptide is composed of 1337 amino acids and possesses most of functional domains and critical residues defined in human and mouse ABCB5/Abcb5. Functional analysis in vitro demonstrated that overexpression of zebrafish abcb5 gene can significantly decrease the cytotoxicity of mercury in LLC-PK1 cells, implying it is a potential efflux transporter of mercury. Thus, these findings provide useful insights to help further understand the transcriptional response and detoxification ability of zebrafish larvae following acute exposure to mercury.
authors.affiliation: Key Laboratory of Freshwater Biodiversity Conservation and Utilization of Ministry of Agriculture, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, Hubei, China. Electronic address: luxing@yfi.ac.cn.
authors.forename: Xing
authors.initials: X
authors.lastname: Lu
authors.affiliation: School of Basic Medical Science, Wuhan University, Wuhan 430071, Hubei, China. Electronic address: xiangy12580@whu.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: School of Basic Medical Science, Wuhan University, Wuhan 430071, Hubei, China. Electronic address: ghyang@whu.edu.cn.
authors.forename: Guohua
authors.initials: G
authors.lastname: Yang
authors.affiliation: School of Basic Medical Science, Wuhan University, Wuhan 430071, Hubei, China. Electronic address: zhanglang211@163.com.
authors.forename: Lang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Basic Medical Science, Wuhan University, Wuhan 430071, Hubei, China; Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, Hubei, China. Electronic address: wanghui19@whu.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Basic Medical Science, Wuhan University, Wuhan 430071, Hubei, China; Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, Hubei, China; Hubei Province Key Laboratory of Allergy and Immunology, Wuhan 430071, Hubei, China. Electronic address: zhongshan@whu.edu.cn.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhong
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D019295:Computational Biology; D030541:Databases, Genetic; D020869:Gene Expression Profiling / Q000379:methods; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D053263:Gene Regulatory Networks; D059014:High-Throughput Nucleotide Sequencing; D018374:LLC-PK1 Cells; D007814:Larva / Q000187:drug effects* / Q000235:genetics; D008627:Mercuric Chloride / Q000378:metabolism / Q000633:toxicity*; D013552:Swine; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects*; D014162:Transfection; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*; D015027:Zebrafish / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D014874:Water Pollutants, Chemical; D029961:Zebrafish Proteins; D008627:Mercuric Chloride
keywords: Abcb5; Gene expression; Mercury; RNA-seq; Zebrafish