Iron deficiency specific cDNA (Ids1) with two homologous cysteine rich mt domains from the roots of barley

Abstract

For the purpose of gene cloning for HAs‐synthesis or Fe(III)‐MAs transporter a ? gt10 cDNA library was constructed from mRNA isolated from Fe‐deficient barley roots. The library was then differentially screened between cDNA probes made from mRNA isolated from barley roots treated with +Fe and ‐Fe. Seven clones which hybridized specifically to the probe of Fe‐deficiency were selected. Their inserts however were too short and not likely to include full length of mRNA. On the basis of these results we decided to screen a newly constructed ? zapII cDNA library with one of the seven clones as a probe and selected a clone presumably having the full length of mRNA compared with northern hybridization. We named this cone as Ids1. The sequenced Ids1 consists of 503 nucleotides containing a putative open reading frame of 222 bp. It encodes a protein of 74 residues (7500 Da) having two cysteine rich domains like animal MT (class I MT).