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Re-partitioning of Cu and Zn isotopes by modified protein expression.

Büchl A, Hawkesworth CJ, Ragnarsdottir KV, Brown DR - Geochem. Trans. (2008)

Bottom Line: Cu and Zn have naturally occurring non radioactive isotopes, and their isotopic systematics in a biological context are poorly understood.We also looked at how altering the expression of a single copper binding protein, the prion protein (PrP), alters the isotope ratios.The results imply that the expression of the prion protein can alter cellular Cu isotope content.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol, BS8 4EU, UK. c.j.hawkesworth@bristol.ac.uk

ABSTRACT
Cu and Zn have naturally occurring non radioactive isotopes, and their isotopic systematics in a biological context are poorly understood. In this study we used double focussing mass spectroscopy to determine the ratios for these isotopes for the first time in mouse brain. The Cu and Zn isotope ratios for four strains of wild-type mice showed no significant difference (delta 65Cu -0.12 to -0.78 permil; delta 66Zn -0.23 to -0.48 permil). We also looked at how altering the expression of a single copper binding protein, the prion protein (PrP), alters the isotope ratios. Both knockout and overexpression of PrP had no significant effect on the ratio of Cu isotopes. Mice brains expressing mutant PrP lacking the known metal binding domain have delta 65Cu isotope values of on average 0.57 permil higher than wild-type mouse brains. This implies that loss of the copper binding domain of PrP increases the level of 65Cu in the brain. delta 66Zn isotope values of the transgenic mouse brains are enriched for 66Zn to the wild-type mouse brains. Here we show for the first time that the expression of a single protein can alter the partitioning of metal isotopes in mouse brains. The results imply that the expression of the prion protein can alter cellular Cu isotope content.

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A plot of δ66Zn versus δ67Zn for all the brains analysed (Table 1) showing that the observed shifts in isotopic ratios lie on the mass fractionation line), and thus they all obey the mass fractionation law. Open triangles – wild mouse strains; filled triangles – prion protein depleted; open circles – TG20; grey squares – C4; grey diamonds – line Harry.
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Figure 1: A plot of δ66Zn versus δ67Zn for all the brains analysed (Table 1) showing that the observed shifts in isotopic ratios lie on the mass fractionation line), and thus they all obey the mass fractionation law. Open triangles – wild mouse strains; filled triangles – prion protein depleted; open circles – TG20; grey squares – C4; grey diamonds – line Harry.

Mentions: Cu and Zn isotopes were analysed by MC-ICP-MS and the results are presented in Table 1. The internal reproducibility for measurement of Cu and Zn isotopes was 0.03‰ (2 sigma). The external reproducibility for Cu and Zn by sample bracketing was 0.08‰ (2 sigma) and for Zn with a double spike 0.04‰ (2 sigma). All the observed shifts in isotopic ratios lie on the mass fractionation line (Fig. 1), and thus they all obey the mass fractionation law.


Re-partitioning of Cu and Zn isotopes by modified protein expression.

Büchl A, Hawkesworth CJ, Ragnarsdottir KV, Brown DR - Geochem. Trans. (2008)

A plot of δ66Zn versus δ67Zn for all the brains analysed (Table 1) showing that the observed shifts in isotopic ratios lie on the mass fractionation line), and thus they all obey the mass fractionation law. Open triangles – wild mouse strains; filled triangles – prion protein depleted; open circles – TG20; grey squares – C4; grey diamonds – line Harry.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2570658&req=5

Figure 1: A plot of δ66Zn versus δ67Zn for all the brains analysed (Table 1) showing that the observed shifts in isotopic ratios lie on the mass fractionation line), and thus they all obey the mass fractionation law. Open triangles – wild mouse strains; filled triangles – prion protein depleted; open circles – TG20; grey squares – C4; grey diamonds – line Harry.
Mentions: Cu and Zn isotopes were analysed by MC-ICP-MS and the results are presented in Table 1. The internal reproducibility for measurement of Cu and Zn isotopes was 0.03‰ (2 sigma). The external reproducibility for Cu and Zn by sample bracketing was 0.08‰ (2 sigma) and for Zn with a double spike 0.04‰ (2 sigma). All the observed shifts in isotopic ratios lie on the mass fractionation line (Fig. 1), and thus they all obey the mass fractionation law.

Bottom Line: Cu and Zn have naturally occurring non radioactive isotopes, and their isotopic systematics in a biological context are poorly understood.We also looked at how altering the expression of a single copper binding protein, the prion protein (PrP), alters the isotope ratios.The results imply that the expression of the prion protein can alter cellular Cu isotope content.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol, BS8 4EU, UK. c.j.hawkesworth@bristol.ac.uk

ABSTRACT
Cu and Zn have naturally occurring non radioactive isotopes, and their isotopic systematics in a biological context are poorly understood. In this study we used double focussing mass spectroscopy to determine the ratios for these isotopes for the first time in mouse brain. The Cu and Zn isotope ratios for four strains of wild-type mice showed no significant difference (delta 65Cu -0.12 to -0.78 permil; delta 66Zn -0.23 to -0.48 permil). We also looked at how altering the expression of a single copper binding protein, the prion protein (PrP), alters the isotope ratios. Both knockout and overexpression of PrP had no significant effect on the ratio of Cu isotopes. Mice brains expressing mutant PrP lacking the known metal binding domain have delta 65Cu isotope values of on average 0.57 permil higher than wild-type mouse brains. This implies that loss of the copper binding domain of PrP increases the level of 65Cu in the brain. delta 66Zn isotope values of the transgenic mouse brains are enriched for 66Zn to the wild-type mouse brains. Here we show for the first time that the expression of a single protein can alter the partitioning of metal isotopes in mouse brains. The results imply that the expression of the prion protein can alter cellular Cu isotope content.

No MeSH data available.


Related in: MedlinePlus