FIGURE 3.

Intein-mediated formation of high molecular weight FLAG proteins in ripening tobacco seeds. FLAG precursor proteins under the control of the USP promoter were analyzed in developing tobacco seeds at 18 DAF (1), 21 DAF (2) and in ripe tobacco seeds (3). Extracts from 31.2 seeds were loaded per lane. Seed extracts were separated by gradient SDS-PAGE (4–10% PAA), and FLAG proteins were visualized by immunodetection based on the c-myc tag. DAF, days after flowering; kDa, kilodalton; WT, wild type.