Abstract
tpoxN1 encodes a tobacco peroxidase gene whose wound-induced expression is insensitive to known wound-signal compounds such as jasmonic acid and ethylene. To study the mechanism of the expression, 2-kbp and successive 5'-deleted tpoxN1 promoters were introduced as GUS fusion genes into tobacco plants. The wound-induced GUS activities indicated that a jA- and ethylene- independent wound-responsive cis-element (JEIW) is present at -239/-200 in 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 the 14-bp region resulted in a decrease in wound-responsive GUS activity in transgenic plants. The 14-bp sequence contains no known wound-responsive cis-elements. Thus, the characteristic tpoxN1 expression is regulated by a novel 14-bp wound-responsive cis-element, JEIW.
