Characterization of metallothionein cDNAs induced by cadmium in the nematode <i>Caenorhabditis elegans</i>

Imagawa, Masayoshi; Onozawa, Takashi; Okumura, Kohji; Osada, Shigehiro; Nishihara, Tsutomu; Kondo, Masayuki

doi:10.1042/bj2680237

Cited by 35 publications

(18 citation statements)

References 11 publications

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“…Tetrahymena metallothioneins contains 30% cysteine, but they are unique and distinct from other metallothioneins, especially with regard to the length of their chains: 105 and 104 residues for metallothionein-1 and metallothionein-2, respectively, in comparison with 61 or 62 residues in mammalian forms, 72 residues in Mytilus [16] and 74 residues in the metallothionein-2 isoform of the nematode Caenorhabditis elegans [17]. Shorter chains are found in Drosophila [18], and in some Ascomicota, e.g.…”

Section: Discussionmentioning

confidence: 99%

Purification and Primary Structure of Metallothioneins Induced by Cadmium in the Protists Tetrahymena Pigmentosa and Tetrahymena Pyriformis

Piccinni

Staudenmann

Albergoni

et al. 1994

European Journal of Biochemistry

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Tetrahymena pyriformis and Tetrahymena pigmentosa grown in the presence of a non-toxic dose of cadmium, accumulate the metal in the cytosol. Purification by gel-permeation, ion-exchange and reverse-phase high-performance liquid chromatography showed that the metal is bound principally to newly formed proteins with ultraviolet spectra and cysteine contents similar to those of CdZ+-metallothioneins from multicellular organisms. The isolated proteins revealed that the two species of ciliates each express two Cd2+-isothioneins. The primary structures determined by both Edman degradation and mass spectrometry revealed that the equivalent proteins from 7: pyriformis and 7: pigmentosa have identical sequences and that the two isoforms in each species differ only by the presence or absence of a lysine residue at the N-terminus. The development of automated mass spectrometric sequence analysis algorithms combined with an accurate determination of the molecular mass allowed the rapid confirmation of the sequences.The Tetrahymena metallothionein sequences are unusually long (105 and 104 amino acids) and show a unique internal homology which suggests that the proteins arose by gene duplication. The chains contain 31 cysteine residues, 15 of which are arranged in motifs characteristic of the mammalian metallothioneins ; the remaining residues show several unique repeating motifs, which could have interesting consequences for the tertiary structure of the metal-binding sites. Amino acid sequences of Tetrahymena metallothioneins have some similarity with other eukaryotic metallothioneins. A comparison on the basis of optimised FASTA scores, shows a closer relationship with horse metallothionein-1B. The first metallothionein was isolated by Margoshes andVallee in 1957 from horse kidney, as a particularly sulphurrich protein containing cadmium [l]. Subsequently, this and other closely related proteins have been shown to be widely distributed amongst prokaryotes and eukaryotes, e.g. in fungi, plants, invertebrates and vertebrates. Metallothioneins are low-molecular-mass, cysteine-rich, aromatic-lacking, metal-binding proteins that are believed to be involved in the regulation of essential trace metals, such as copper and zinc, and detoxification of these metals when present in excess, as well as non-essential metals. The preponderance of cysteine residues allows the metal ions to be bound by the formation of clusters of metal-thiolate complexes. Metallothioneins can be classified into the following three groups based on the arrangement of the cysteine residues in the primary structure: class I with a distribution like horse kidney metallothionein; class I1 with a distribution weakly related to class I; class 111, Correspondence to E. Piccinni, Dipartimento di Biologia, Via 19).Note. The novel amino acid sequence data published here have been submitted to the EMBL sequence data bank and is available under accession number P80394. The characteristic features of mammalian metallothioneins have been widely studied and many of the pr...

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Section: Discussionmentioning

confidence: 99%

Purification and Primary Structure of Metallothioneins Induced by Cadmium in the Protists Tetrahymena Pigmentosa and Tetrahymena Pyriformis

Piccinni

Staudenmann

Albergoni

et al. 1994

European Journal of Biochemistry

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“…In addition, significant levels of intestinal cell transcription of C. elegans MTs are difficult to be observed in the absence of stress [32]–[34]. In the present study, our data demonstrate that the defects of adaptive response to neurobehavioral toxicity induced by metal exposure formed in mtl-1 and mtl-2 mutants could be not only completely rescued by the expression of mtl-1 or mtl-2 with the aid of its own promoter, but also largely rescued by the expression of mtl-1 or mtl-2 gene in the nervous system (D.-Y.…”

Section: Discussionmentioning

confidence: 99%

“…MTs may be involved in the detoxication of heavy metals, such as cadmium (Cd) and mercury (Hg), the homoeostasis of essential metals such as zinc (Zn) and copper (Cu), and the protection against intracellular oxidative damage [32]–[33]. The MT transcription can be induced by metal exposure, ionizing radiation, heat-shock, and oxidative stress [33]–[35].…”

Section: Introductionmentioning

confidence: 99%

Metallothioneins Are Required for Formation of Cross-Adaptation Response to Neurobehavioral Toxicity from Lead and Mercury Exposure in Nematodes

Rui

et al. 2010

PLoS ONE

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Metallothioneins (MTs) are small, cysteine-rich polypeptides, but the role of MTs in inducing the formation of adaptive response is still largely unknown. We investigated the roles of metallothionein genes (mtl-1 and mtl-2) in the formation of cross-adaptation response to neurobehavioral toxicity from metal exposure in Caenorhabditis elegans. Pre-treatment with mild heat-shock at L2-larva stage effectively prevented the formation of the neurobehavioral defects and the activation of severe stress response in metal exposed nematodes at concentrations of 50 and 100 µM, but pre-treatment with mild heat-shock did not prevent the formation of neurobehavioral defects in 200 µM of metal exposed nematodes. During the formation of cross-adaptation response, the induction of mtl-1 and mtl-2 promoter activity and subsequent GFP gene expression were sharply increased in 50 µM or 100 µM of metal exposed Pmtl-1::GFP and Pmtl-2::GFP transgenic adult animals after mild heat-shock treatment compared with those treated with mild heat-shock or metal exposure alone. Moreover, after pre-treatment with mild heat-shock, no noticeable increase of locomotion behaviors could be observed in metal exposed mtl-1 or mtl-2 mutant nematodes compared to those without mild heat-shock pre-treatment. The defects of adaptive response to neurobehavioral toxicity induced by metal exposure formed in mtl-1 and mtl-2 mutants could be completely rescued by the expression of mtl-1 and mtl-2 with the aid of their native promoters. Furthermore, over-expression of MTL-1 and MTL-2 at the L2-larval stage significantly suppressed the toxicity on locomotion behaviors from metal exposure at all examined concentrations. Therefore, the normal formation of cross-adaptation response to neurobehavioral toxicity induced by metal exposure may need the enough accumulation of MTs protein in animal tissues.

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“…In the absence of cadmium no staining is observed (A) (adapted from Freedman et al, 1993). a novel C-terminal extension (Slice et al, 1990;Imagawa et al, 1990). Freedman et al (1993) and later Liao and Freedman (1998) reported the sequences of the coding and flanking regions of the mtl-1 and mtl-2 genes, which encode CeMT1 and CeMT2, respectively.…”

Section: Regulation Of Metalothionein Transcriptionmentioning

confidence: 99%

“…When C. elegans is exposed to >50 |iM CdCI 2 , two iso-MTs, designated CeMT1 (75 amino acid residues) and CeMT2 (63 residues), accumulate in substantial amounts (Slice et al, 1990;Imagawa et al, 1990). These two polypeptides are cysteine-rich (25-30%) and exhibit characteristic Cys-XCys and Cys-Cys motifs (Slice et al, 1990;Imagawa et al, 1990). However, the amino acid sequences of C. elegans MTs are not homologous with MTs from other species.…”

Section: Regulation Of Metalothionein Transcriptionmentioning

confidence: 99%

Cadmium‐induced gene expression is regulated by MTF‐1, a key metal‐responsive transcription factor

Gupta

Ahnn

2003

Korean Journal of Biological Sciences

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Characterization of metallothionein cDNAs induced by cadmium in the nematode Caenorhabditis elegans

Cited by 35 publications

References 11 publications

Purification and Primary Structure of Metallothioneins Induced by Cadmium in the Protists Tetrahymena Pigmentosa and Tetrahymena Pyriformis

Purification and Primary Structure of Metallothioneins Induced by Cadmium in the Protists Tetrahymena Pigmentosa and Tetrahymena Pyriformis

Metallothioneins Are Required for Formation of Cross-Adaptation Response to Neurobehavioral Toxicity from Lead and Mercury Exposure in Nematodes

Cadmium‐induced gene expression is regulated by MTF‐1, a key metal‐responsive transcription factor

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