A novel wound-responsive cis-element, VWRE, of the vascular system-specific expression of a tobacco peroxidase gene, tpoxN1.
The wound-induced expression of tpoxN1, encoding a tobacco peroxidase, is unique because of its vascular system-specific expression and insensitivity to known wound-signal compounds such as jasmonic acid, ethylene, and plant hormones [Sasaki et al. (2002) Plant Cell Physiol 43:108-117]. To study the mechanism of expression, the 2-kbp tpoxN1 promoter region and successive 5'-deletion of the promoter were introduced as GUS fusion genes into tobacco plants. Analysis of GUS activity in transgenic plants indicated that a vascular system-specific and wound-responsive cis-element (VWRE) is present at the -239/-200 region of the promoter. Gel mobility shift assays suggested that a nuclear factor(s) prepared from wounded tobacco stems binds a 14-bp sequence (-229/-215) in the -239/-200 region in a sequence-specific manner. A mutation in this 14-bp region of the -239 promoter fragment resulted in a considerable decrease in wound-responsive GUS activity in transgenic plants. An 11-bp sequence, which completely overlaps with the 14-bp sequence, was found in the 5' distal region (-420/-410) and is thought to contribute to the wound-induced expression together with the 14-bp. The -114-bp core promoter of the tpoxN1 gene was indispensable for wound-induced expression, indicating that the 14-bp region is a novel wound-responsive cis-element VWRE, which may work cooperatively with other factors in the promoter.
Sasaki
Katsutomo
K
Division of Plant Sciences, Organization of National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan.
Ito
Hiroyuki
H
Mitsuhara
Ichiro
I
Hiraga
Susumu
S
Seo
Shigemi
S
Matsui
Hirokazu
H
Ohashi
Yuko
Y
D001483:Base Sequence; D017931:DNA Primers; D017343:Genes, Plant; D010544:Peroxidases / Q000235:genetics*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D014026:Nicotiana / Q000201:enzymology*
D017931:DNA Primers; D010544:Peroxidases