A novel iron-regulated metal transporter from plants identified by functional expression in yeast.

TLDR

Iron is an essential nutrient for virtually all organisms, and related sequences are found in rice, yeast, nematodes, and humans. The IRT1 gene from Arabidopsis thaliana, encoding a probable Fe(II) transporter, was cloned by functional expression in a yeast strain defective for iron uptake. Yeast expressing IRT1 exhibit a novel Fe(II) uptake activity inhibited by Cd, and IRT1 is an integral membrane protein with a metal‑binding domain that belongs to a gene family in Arabidopsis, is expressed in roots, induced by iron deficiency, and its regulation is altered in mutants affecting iron uptake, providing the first molecular insight into plant iron transport.

Abstract

Iron is an essential nutrient for virtually all organisms. The IRT1 (iron-regulated transporter) gene of the plant Arabidopsis thaliana, encoding a probable Fe(II) transporter, was cloned by functional expression in a yeast strain defective for iron uptake. Yeast expressing IRT1 possess a novel Fe(II) uptake activity that is strongly inhibited by Cd. IRT1 is predicted to be an integral membrane protein with a metal-binding domain. Data base comparisons and Southern blot analysis indicated that IRT1 is a member of a gene family in Arabidopsis. Related sequences were also found in the genomes of rice, yeast, nematodes, and humans. In Arabidopsis, IRT1 is expressed in roots, is induced by iron deficiency, and has altered regulation in plant lines bearing mutations that affect the iron uptake system. These results provide the first molecular insight into iron transport by plants.