The plant zinc finger protein ZPT2-2 has a unique mode of DNA interaction.
ZPT2-2 is a DNA-binding protein of petunia that contains two canonical TFIIIA-type zinc finger motifs separated by a long linker. We previously reported that ZPT2-2 bound to two separate AGT core sites, with each zinc finger making contact with each core site. Here we present our further characterization of ZPT2-2 by using selected and amplified binding sequence imprinting and surface plasmon resonance analyses; together, these assays revealed some unusual features of the interaction between ZPT2-2 and DNA. These experiments allowed us to conclude that 1) the optimal binding sequence for the N-terminal zinc finger is AGC(T), and that of the C-terminal one is CAGT; 2) multiple arrangements of the two core sites accommodate binding; and 3) the spacing between the two core sites affects the binding affinity. In light of these observations, we propose a new model for the DNA-ZPT2-2 interaction. Further, consistent with this model, a high affinity binding site for ZPT2-2 was found in the promoter region of the ZPT2-2 gene. This site may serve as a cis-element for the autoregulation of ZPT2-2 gene expression.
Yoshioka
K
K
Department of Biological Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda, Chiba, Japan.
Fukushima
S
S
Yamazaki
T
T
Yoshida
M
M
Takatsuji
H
H
D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D015342:DNA Probes; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D010944:Plants / Q000737:chemistry*; D011485:Protein Binding; D016335:Zinc Fingers
D015342:DNA Probes; D010940:Plant Proteins; D004247:DNA