Identification of protein-binding DNA sequences in an auxin-regulated gene of soybean.
The promoter region of a soybean auxin-responsive gene, GmAux28, was analyzed to identify protein-binding DNA sequences that may be involved in regulation of expression. Using DNase I footprinting and gel mobility shift assays, multiple regions of interaction, including eight major protein-binding sites, were observed in the GmAux28 gene. Two sequence motifs, TGACGACA and TCCACGTGTC, related to as-1/Hex and G-box elements, respectively, found in several plant promoters, were identified. Four distinct A/T-rich domains were identified; such A/T-rich domains appear to modulate, but not to specify, the expression of many genes. Two new sequence motifs, delta-1 (D1) and delta-4 (D4) were also identified. D1 and D4 share a very similar core sequence, TAGTxxCTGT and TAGTxCTGT, respectively. In gel mobility shift analyses, D1 and D4 elements exhibit a complex interaction of binding proteins. The GmAux22 promoter also contains D1-related elements which compete with the GmAux28 elements. Sequence comparisons have identified D1/D4-like sequences in several other auxin-responsive genes suggesting the possible importance of D1/D4 and the respective binding proteins in the regulation of expression of these genes.
Nagao
R T
RT
Department of Botany, University of Georgia, Athens 30602.
Goekjian
V H
VH
Hong
J C
JC
Key
J L
JL
D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D017343:Genes, Plant; D007210:Indoleacetic Acids / Q000502:physiology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D013025:Glycine max / Q000235:genetics*
D004268:DNA-Binding Proteins; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D004247:DNA