Applications And Functional Analysis Of Tobacco TM2 In Transgenic Plants

Both practical applications and basic research of gene transfer technology are sometimes severely handicapped by transgene silencing and instability of gene expression. Matrix attachment regions (MARs) have recently been seen as fundamental tools to reduce or eliminate some forms of transgene silencing because of their capacity to increase transgene expression levels or reduce the variance between transgenic events when flanking a transgene cassette in both plants and animals.Different kinds of MARs have been isolated and studied from a diverse range of eukaryotes such as yeasts, plants, and animals. In higher plants, studies about MARs are mainly focused on the effect of enhancing transgene expressions and the influences on transformant variabilities. Different MARs have different functions. Due to the diversity of the function of different MARs, it is necessary to obtain MARs that can be widely used to improve transgene expression in various crops.We have been interested in isolating and identifying strong MARs that could be used to improve transgene expression. TM2, a new DNA fragment isolated from tobacco, can bind with the rice nuclear matrix in vitro. In this study, we investigated the effect of TM2 on transgene expression under the control of three different promoters in stably transformed tobacco and rice. We also investigated the functional mechanism of TM2, The main results were as follows:1. Through the separation of matrix attachment regions in tobacco, we constructed a library of DNA sequences that were copurified with a tobacco nuclear matrix. TM2, a new 1001 bp DNA fragment isolated from tabacco, can bind with the rice nuclear matrix in vitro with a high binding ability. One T-box, two unwinding sites and one Toposomerase II binding...