title: DNA binding of citrus dehydrin promoted by zinc ion.
abstract: Dehydrins are hydrophilic proteins that accumulate during embryogenesis and osmotic stress responses in plants. Here, we report an interaction between citrus dehydrin Citrus unshiu cold-regulated 15 kDa protein (CuCOR15) and DNA. Binding of CuCOR15 to DNA was detected by an electrophoretic mobility shift assay, a filter-binding assay and Southwestern blotting. The binding was stimulated by physiological concentrations of Zn2+, but little stimulation occurred when other divalent cations, such as Mg2+, Ca2+, Mn2+, Ni2+ and Cu2+, were substituted for Zn2+. Ethylenediaminetetraacetic acid cancelled the Zn2+-stimulated binding. A binding curve and competitor experiments suggested that the DNA binding of CuCOR15 exhibited low affinity and non-specificity. Moreover, tRNA competed with the DNA binding. Histidine-rich domains and a polylysine segment-containing domain participated in the DNA binding. These results suggest that CuCOR15 can interact with DNA, and also RNA, in the presence of Zn2+. Dehydrin may protect nucleic acids in plant cells during seed maturation and stress responses.
authors.affiliation: Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan. masahara@agr.shizuoka.ac.jp
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hara
authors.forename: Yuri
authors.initials: Y
authors.lastname: Shinoda
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Toru
authors.initials: T
authors.lastname: Kuboi
mesh_terms: D002413:Cations, Divalent / Q000378:metabolism; D002957:Citrus / Q000378:metabolism*; D018744:DNA, Plant / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D011485:Protein Binding; D018749:RNA, Plant / Q000378:metabolism; D015032:Zinc / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D018749:RNA, Plant; C070556:dehydrin proteins, plant; D015032:Zinc