Construction And Identification Of Fruit-specific Expression Vectors

The tomato 2A11 gene is expressed in a strictly fruit-specific manner. 2A11 mRNA levels are about 0.01% of the mRNA in the immature green stage and about 1% in red fruit, and there are at least three general enhancer elements, three negative regulatory elements and four fruit-specific enhancer elements in 2A11 5` 1.8kb region. First, we cloned the 2A11 1.8kb promoter and then the four fruit-specific enhancer elements named F1, F2, F3 and F4 by PCR. We rebuilt five expression vectors (pFS1, pFS2, pFS3, pFS4 and pFS5) by linking these elements in different orientation. Though leaf disc transformation, some transgenic tobacco plants were obtained. The detail characteristics were investigated by histochemical and quantitive analysis of GUS activity in fruits, leaves, stems and roots of transgenic plants. GUS activities were detected in transgenic tobacco fruits, but not in other tissues. It is different from the previous date that 2A11::GUS activity was not able to be detected any GUS activity in leaf tissue or flower tissue, including tobacco ovaries (fruits). At last, we discussed the expression activity of the five vectors at fruit different development stages of the transgenic tobacco and the new function of enhancer at gene expression regulation.