Assembling the pieces

Abstract

Transition metals function as cofactors in specific proteins, catalyzing electron exchange reactions, binding substrates and stabilizing protein structure. Studies of human diseases and of model organisms have defined many of the molecular details of metal uptake, trafficking, and excretion. The current challenge is to integrate these details into a systematic view of metal content, speciation, localization and use within organisms and ecosystems.

Figure 1

X-ray fluorescence microtomography of Arabidopsis seed. X-ray fluorescence tomographic slices of Fe K (blue), Mn K (green), and Zn K (red) fluorescence lines collected from wild-type Col-0 and vit1-1 seeds, with metal abundances indicated in mg kg⁻¹ (smaller images) and composite images of iron, manganese and zinc (larger images). Iron in wild-type seeds is localized to the provascular trands of the hypocotyl, radicle and cotyledons, whereas in vit1-1 seeds, it is absent from these cells and located diffusely in the hypocotyl and radicle and epidermal cells of the cotyledons. Modified with permission from ref. .

Figure 2

Gene dosage of atp7a reveals a developmental hierarchy of copper metabolism. (a–c) The copper chelator neocuproine at 100 nM is without effect on melanin pigmentation in wild-type embryos (a), whereas this same dose prevents melanin pigment in atp7a (calamity) heterozygotes (b) and worsens the abnormal brain and notochord phenotype in atp7a homozygotes (c). Modified with permission from ref. .