Effects of Upstream Region Deletion on Rice sbe1 Gene Expression
CAI Yi XIE Dong-Lu WANG Zong-Yang HONG Meng-Min (Shanghai Institute of Plant Physiology, Chinese Academy of Sciences, Shanghai 200032)
To identify the cis-acting elements within the 5′-upstream region of rice sbe1 gene, four deletion mutants were constructed by digestion of the sbe1 promoter from the 5′ end with restriction enzymes and ExoIII (Figs.1,2). Each of the chimeric genes consisting of these deleted sequences and coding sequence of β-glucuronidase (gus) gene was respectively introduced into rice plants mediated by Agrobacterium and the expression of the chimeric gene in immature seeds of transgenic plants was examined (Fig.3). The data showed that the-516-+64 bp fragment of sbe1 promoter can drive the high-level expression of gus gene, while the other three promoter fragments ( -1 096-+74 bp, -295-+74 bp, -146-+64 bp) can only drive a low-level expression of gus gene. These results suggested that there were possible positive elements in the region from -516 bp to-295 bp which can enhance the expression of the gus gene.