The RY sequence is necessary but not sufficient for the transcription activation of a winged bean chymotrypsin inhibitor gene in developing seeds.
A winged bean Kunitz-type chymotrypsin inhibitor (WCI) is expressed in seeds and tuberous roots. In seeds, the expression of WCI is restricted to the period between the mid- and late-maturation stage. To understand the mechanisms that regulate the expression of WCI genes, we analyzed the promoter activity of the upstream region of the WCI-3b gene, which encodes a major WCI protein, in transgenic tobacco plants. By using a series of constructs with 5' deletions in the upstream sequences, the region between -882 and -623, relative to the transcription start site, was shown to contain multiple sequences which are responsible for high level expression in mid-maturation stage seeds. However, when this region was fused to the cauliflower mosaic virus 35S core promoter in both orientations, the chimeric promoters showed only a weak transcription activity in transgenic tobacco plants. Further analyses using internal deletion constructs revealed that the region between -882 and -174 is required for the transcription activation. Disruption of the RY sequence at -517, which is conserved in many seed protein genes, resulted in a drastic reduction of the transcription activity in seeds. These results suggest that sequences necessary for high level induction of the WCI-3b gene transcription in developing seeds are dispersed in the region between -882 and -174, and that the RY sequence is one of these sequences.
Sakata
Y
Y
Department of Applied Bioscience, Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
Chiba
Y
Y
Fukushima
H
H
Matsubara
N
N
Habu
Y
Y
Naito
S
S
Ohno
T
T
D002918:Chymotrypsin / Q000235:genetics*; D007887:Fabaceae / Q000235:genetics; D017343:Genes, Plant / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics; D030821:Plants, Genetically Modified; D010946:Plants, Medicinal; D010947:Plants, Toxic; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid / Q000502:physiology*; D012639:Seeds / Q000235:genetics; D014026:Nicotiana / Q000235:genetics; D015533:Transcriptional Activation; D014361:Trypsin Inhibitors / Q000235:genetics*
D010940:Plant Proteins; D014361:Trypsin Inhibitors; D002918:Chymotrypsin