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Biochemical Journal logoLink to Biochemical Journal
. 2002 Jul 1;365(Pt 1):323–328. doi: 10.1042/BJ20011751

Sheep have an unusual variant of the brain-specific metallothionein, metallothionein-III.

Roger S Chung 1, Adele F Holloway 1, Bedrich L Eckhardt 1, Julie A Harris 1, James C Vickers 1, Meng Inn Chuah 1, Adrian K West 1
PMCID: PMC1222643  PMID: 11931634

Abstract

Sheep metallothionein-III (MT-III) cDNA was isolated from a brain cDNA library and characterized. In contrast with MT-III from other species, sheep MT-III cDNA is predicted to encode a protein with significantly different metal-binding properties, owing to the loss of three of its cysteine residues. RT-PCR from other sheep confirmed that this aberrant structure is ubiquitous in this species. MT-III was successfully isolated from sheep brain, demonstrating that the cDNA does give rise to a protein product of the predicted structure. Sheep MT-III is similar to other mammalian MT-IIIs in that it retains the Cys-Pro-Cys-Pro motif which is thought to encode growth-inhibitory activity, and we show that it is likewise able to inhibit neuron survival in vitro. This is the first naturally occurring variant of MT-III (or any other major mammalian MT gene) which gives rise to a protein product. These findings are discussed in light of proposed roles of MT in the mammalian brain.

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Selected References

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