Tobacco matrix attachment region sequence increased transgene expression levels in rice plants

In this study, six plasmids were constructed to study the effects of the to bacco Rb7 matrix attachment region (MAR) sequence on rice transgene express ion. Among them, each of four plasmids contained two identical copies of th e MAR sequence flanking two different reporter genes, which encode the gree n fluorescent protein and beta -glucuronidase. Two control plasmids contain ed no MAR sequences. Microprojectile bombardment was used to separately int roduce these six plasmids into rice calli. Transgenic rice plants were rege nerated, and gene expression was measured in rice leaf extracts of two-mont h-old transgenic plants. By comparing transgenic plants with the correspond ing control plants, transgenic plants harboring each of four plasmids that included the MAR sequence resulted in average gene expression levels enhanc ed by 3.3-fold, 18-fold, 376-fold and 650-fold. These results suggest that the same MAR sequence can affect the expression of different genes to diffe rent extents. One goal of plant scientists and breeders is to maximize expr ession levels of transgenes, especially in the production of transgene-enco ded protein. Therefore, inclusion of the Rb7 MAR sequence would be benefici al.