title: Expression and function analysis of metallothionein in the testis of stone crab Charybdis japonica exposed to cadmium.
abstract: Metallothionein (MT) participates in metallic homeostasis and detoxification in living animals. Previous studies have focused mainly on the functions of MT in vertebrates, but the functions of MT during spermiogenesis in invertebrates remain unclear. In order to investigate the functions of MT during spermiogenesis in the Japanese stone crab (Charybdis japonica), we identified the C. japonica MT complete cDNA sequence from the total RNA of the testis using RT-PCR and RACE. The 587 bp MT cDNA contains: an 80 bp 5' untranslated region, a 333 bp 3' untranslated region, and a 174 bp open reading frame. MT has 57 amino acids including 19 cysteines. The protein alignment between MT sequences of C. japonica and other crabs shows a high similarity and a strong identity in cysteine residues vital for the metal-binding affinity of MT. After the cadmium (Cd) exposure, the testis displays both abnormal morphology and MT mRNA expression both of which indicate a sensitive response of testis MT to Cd. Therefore, we suggest that MT is an excellent biomarker candidate for evaluating Cd pollution.
authors.affiliation: The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Huan
authors.initials: H
authors.lastname: Mao
authors.forename: Fu-Qing
authors.initials: FQ
authors.lastname: Tan
authors.forename: Da-Hui
authors.initials: DH
authors.lastname: Wang
authors.forename: Jun-Quan
authors.initials: JQ
authors.lastname: Zhu
authors.forename: Hong
authors.initials: H
authors.lastname: Zhou
authors.forename: Wan-Xi
authors.initials: WX
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003386:Brachyura / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D002104:Cadmium / Q000633:toxicity*; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D008297:Male; D008668:Metallothionein / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D013737:Testis / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D004272:DNA, Mitochondrial; D014874:Water Pollutants, Chemical; D002104:Cadmium; D008668:Metallothionein