Construction Of ACT E3/GUS Fusion Gene And Analysis Of ACT E3 Promoter Activity In Transgenic Tobacco Plants

ACT E3 is an actin promoter that was isolated from cotton in our lab. By molecular Diological methods, the promoter ACT E3 was fused with GUS reporter gene to construct the expression vector pACT E3. Then the ACT E3/GUS fusion gene was introduced into tobacco via Agrobacterium-mediated transformation and got the transformed plants. The genome DNA from the transformed plants was used as template to do PCR reaction of NPT II gene and GUS gene. The results of PCR reaction showed that foreign genes have been integrated into the transgenic tobacco genome. GUS histochemical assay indicated that the GUS activity is different in diverse tissues of transgenic plants. High levels or low levels of GUS expression were detected in different tissues such as stems, leaves, sepals, petals, anthers, stigmas, ovaries, fruits, but no GUS staining was found in other tissues of transgenic plants. This result indicated that the ACT E3 promoter directed GUS gene to be expressed predominantly in stems, leaves, sepals, petals, anthers, stigmas, ovaries, fruits. In different development stages of the tobacco transgenic plants, the levels of GUS expression were different. This result demonstrated that the activity of ACT E3 promoter is developmental-regulated. The experimental results not only offer new data on studying the regulation of plant gene expression, but also provide a new promoter for expressing the target genes in the important crops.