Characterization of a single copy gene encoding ferredoxin I from pea

We have isolated, mapped, and sequenced a genomic clone containing the ferredoxin I (Fed-1) gene from Pisum sativum. The gene is present as a single copy per haploid genome. It has no introns, and it specifies a 753-nucleotide transcript encoding a 149-amino acid protein including a 52-residue transit peptide. Upstream sequences from Fed-1 contain several elements with similarity to transcriptional regulatory elements from RbcS and Cab genes, and gel mobility shift assays show that nuclear extracts from light-grown pea leaves contain one or more DNA binding activities specific for Fed-1 5'-flanking sequences. RbcS and Cab regulatory sequences are only weak competitors for this binding, however, and the RbcS and Cab similarities mostly lie outside of the region essential for binding. These data are discussed in terms of previously observed physiological differences between the light responses of Fed-1 and other genes.