The physiological function of metallothionein

Brady, F.

doi:10.1016/0968-0004(82)90206-7

Cited by 152 publications

(60 citation statements)

References 15 publications

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“…Metallothioneins are implicated in metal homeostasis and detoxification (7). Bacteria have evolved a wide range of mechanisms for dealing with toxic levels of metals in their environment including methylation, precipitation, chelation, and exclusion (8,9).…”

Section: Introductionmentioning

confidence: 99%

Cadmium-binding proteins in Pseudomonas putida: pseudothioneins.

Higham¹,

Sadler²,

Scawen³

1986

Environ Health Perspect

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Pseudomonas putida adapted to growth in 3 mM cadmium. The resistance mechanism involved complexation of cadmium in polyphosphate granules, changes in the structure of the cell membrane and induction of three cysteine-rich, low molecular weight proteins (3500-7000) containing 4 to 7 g-atoms per mole of cadmium, zinc, and copper. Each protein was produced during a different phase of growth, and the smallest protein (3500) was released into the environment when the cells lysed at the end of the exponential phase.The metal binding sites of the major protein were further characterized using a range of physical methods, including 118Cd NMR. The properties of the bacterial pseudothioneins are compared to those of metallothioneins.

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Section: Introductionmentioning

confidence: 99%

Cadmium-binding proteins in Pseudomonas putida: pseudothioneins.

Higham¹,

Sadler²,

Scawen³

1986

Environ Health Perspect

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“…In contrast to the detailed knowledge on the molecular structure and the physical-chemical properties of the metal-binding sites of metallothioneins, their biological function is still a matter of controversy. Besides a metal detoxification and storage function [2], metallothioneins were also proposed to be involved in metal transfer to apometalloproteins. In particular, the zinc ions of metallothioneins were reported to reactivate a number of zinc-dependent enzymes [2].…”

Section: Introductionmentioning

confidence: 99%

“…Besides a metal detoxification and storage function [2], metallothioneins were also proposed to be involved in metal transfer to apometalloproteins. In particular, the zinc ions of metallothioneins were reported to reactivate a number of zinc-dependent enzymes [2].…”

Section: Introductionmentioning

confidence: 99%

Copper transfer between Neurospora copper metallothionein and type 3 copper apoproteins

Beltramini

Lerch

1982

FEBS Letters

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“…However, MT mRNA and protein levels each indicate that MT-1 and MT-2 expression is non-coordinate in uninduced cells. Thus, regulation of MT expression may involve two different mechanisms which are differentially operative in induced and uninduced cells.The genomes of mammals encode two closely related metallothioneins (MTs), MT-1 and MT-2, whose expression is induced coordinately by either metals or glucocorticoids (1,13,17). Two different mechanisms have been advanced to account for the coordinate induction of mammalian MT genes.…”

mentioning

confidence: 99%

“…The genomes of mammals encode two closely related metallothioneins (MTs), MT-1 and MT-2, whose expression is induced coordinately by either metals or glucocorticoids (1,13,17). Two different mechanisms have been advanced to account for the coordinate induction of mammalian MT genes.…”

mentioning

confidence: 99%

Coordinate expression of amplified metallothionein I and II genes in cadmium-resistant Chinese hamster cells.

Griffith¹

1985

Mol. Cell. Biol.

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Recombinant DNA probes complementary to Chinese hamster metallothionein (MT)-1 and MT-2 mRNAs were used to compare MT gene copy numbers, zinc-induced MT mRNA levels, and uninduced MT mRNA levels in cadmium-resistant (Cdr) Chinese hamster ovary cell lines. Quantitative hybridization analyses determined that the MT-1 and MT-2 genes are each present at approximately single-copy levels in the genome of cell line Cdr2C1O and are coordinately amplified approximately 7, 3, and 12 times over the Cdr2C1O value in the genomes of cell lines Cdr2OF4, Cdr3OF9, and Cdr200Tl, respectively. The maximum zinc-induced MT-1 mRNA concentrations in cell lines Cdr2OF4, CdF3OF9, and Cdr200Ti were equal to 1, 3, and 15 times that measured in Cdr2C1O, respectively. Similarly, the maximum zinc-induced MT-2 mRNA concentrations were equal to 1, 3, and 14 times that measured in Cdr2C1O, respectively, and in each instance they were 90 to 150 times greater than their respective concentrations in uninduced cells. Thus, relative MT gene numbers are closely correlated with both zinc-induced and uninduced MT mRNA levels in CdF2C10, Cdr3OF9, and Cdr200Tl, but not in Cdr2OF4. Each of the latter two lines possesses structurally altered chromosomes whose breakpoints are near the MT locus. Nonetheless, the ratio of the levels of MT-1 to MT-2 mRNAs was constant in each of the four cell lines, including Cdr2OF4. These results demonstrate that MT-1 and MT-2 mRNAs are induced coordinately in each Cdr cell line. Therefore, the coordination of the induction of MT-1 and MT-2 mRNA is independent of MT gene amplification, MT gene rearrangement, and the relative inducibilities of amplified MT genes. However, MT mRNA and protein levels each indicate that MT-1 and MT-2 expression is non-coordinate in uninduced cells. Thus, regulation of MT expression may involve two different mechanisms which are differentially operative in induced and uninduced cells.The genomes of mammals encode two closely related metallothioneins (MTs), MT-1 and MT-2, whose expression is induced coordinately by either metals or glucocorticoids (1,13,17). Two different mechanisms have been advanced to account for the coordinate induction of mammalian MT genes. The first has been proposed to explain human MT regulation and is based on differences in the gene dosage and relative inducibilities of the human MT-1 and MT-2 genes. In humans, the MT gene cluster is composed of several functional MT genes and nonfunctional pseudogenes which are located at a number of different chromosomal loci (12,18,19). Mutagenesis and gene transfer experiments have identified regulatory regions upstream from each human MT gene promoter. The sequences upstream from the MT-2 promoter mediate transcription induction by zinc, cadmium, and glucocorticoids (12). In contrast, the sequences upstream from the MT-1 promoter mediate transcription induction by cadmium but are much less responsive to zinc and glucocorticoids (18). Nonetheless, since there are more MT-1 than MT-2 genes, both MT species can be induced coordinately...

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The physiological function of metallothionein

Cited by 152 publications

References 15 publications

Cadmium-binding proteins in Pseudomonas putida: pseudothioneins.

Cadmium-binding proteins in Pseudomonas putida: pseudothioneins.

Copper transfer between Neurospora copper metallothionein and type 3 copper apoproteins

Coordinate expression of amplified metallothionein I and II genes in cadmium-resistant Chinese hamster cells.

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