TA3 Metals in the Environment: Aquatic Biological Perspectives
254 Portland Ballroom
8:00 AM - 12:00 PM, Tuesday
() Molecular and genomics approaches to understand regulation and toxicity of zinc in fish.
Hogstrand, C1, Qiu, A1, Balesaria, S1, Zheng, D1, Feeney, G2, Kille, P2, 1 King's College London, Department of Life Sciences, London, UK2 Cardiff School of Biosciences, Cardiff, UK
ABSTRACT- Through physiological studies it is clear that uptake of zinc from water and diet are regulated transporter-mediated processes. It has also been shown that toxicity of zinc is related to its ability to interfere with calcium uptake. Using comparative genomics we have identified several zinc transporters in rainbow trout, zebrafish and Takifugu rubripes. These transporters, which may serve as molecular sites for zinc uptake, belong to three protein families, ZIP, ZnT, and TRPV. Whereas ZIP and ZnT proteins appear to be dedicated zinc transporters that move zinc in and out of the cytoplasm, respectively, TRPV6 is an epithelial calcium channel that is also highly permeable to zinc. Thus, the latter provides a defined locus for the competition between zinc and calcium at the teleost gill. Functional characterization shows that different zinc transporters have distinct characteristics and behave uniquely in response to changes in concentrations of competing cations. Expression of zinc transporters and chaperones (i.e. metallothionein, glutathione) changes according to demand and is regulated to avoid toxicity. Through mapping of the individual entities involved in metal regulation and characterization of their properties, we hope to improve the parameters that go into dynamic models of metal bioavailability and toxicity.
Key words: fish, zinc, transport, molecular