RESUMO
AIM: To investigate transcriptional regulatory properties of DNA sequence upstream of the ezrin gene promoter in nasopharyngeal carcinoma CNE2 cells. METHODS: A series of reporter gene expression vectors carrying ezrin-1541/-706 sequence were constructed. In forward or reverse orientation, the ezrin -1541/-706 segment was located upstream of the luc gene in pGL3-Basic, upstream of the ezrin promoter or SV40 promoter, or downstream of the luc gene controlled by ezrin promoter or SV40 promoter. These plasmids were transfected into CNE2 cells for luciferase assay. RESULTS: In CNE2 cells, when the ezrin -1541/-706 was located upstream of luc gene in pGL3-Basic in the forward orientation, it exhibited transcriptional activation about 50% of ezrin promoter; while this transactivation nearly abolished when this segment was reversed. When this segment was located upstream of the ezrin promoter or SV40 promoter in the forward orientation, it dramatically increased luciferase expression. However, the transcriptional enhancement disappeared when this segment was located upstream of promoters in the reverse orientation, or downstream of reporter genes in the forward or reverse orientation. CONCLUSION: In CNE2 cells, the DNA sequence upstream of the ezrin promoter could exhibit transcriptional activation and enhancement, in a position- and orientation-dependent manner.
