The Mini Ds Transposon Negatively Regulates the epsps Gene Expression after Insertion into 5'UTR or Intron 1

Transposable elements (TE) are mobile DNA fragments in plant genome. It has been shown that insertion of TE may regulate the flanking genes, acting as a cis-regulating element to exert enhancing or silencing effects. Such regulating capacity has been reported to be influenced by the insertional site, especially significantly in 5’ UTR and the first intron. Much research has been drawn to the study of high-throughput analysis, with an eye to discuss the overall impact on genome. Relatively less, however, focuses on quantitative analysis and valid assessment of the effect of a single TE on a gene in different insertion sites. In this study, four constructs, where a mini Ds-inserted epsps gene in 5’ UTR or the first intron in either orientation and a reference gene are adjacently designed in T-DNA, were introduced into rice. The expression differences are assessed through semi-quantitative and quantitative RT-PCR. The relative expression levels of the mini Ds-inserted genes, by either orientation and by both insertion sites, were significantly lower than the reference. Based on the results, the orientations of the insertion, the influence of TE insertion on gene expression, and the assessment of the research are deliberated for deeper understanding of the interaction between the TE and the host genome.