Promoter Analysis of Krüppel-like Factor 5 Gene

Objectives: Krüppel-like factor 5 (KLF5) is a zinc-finger transcriptional factor that is expressed in basal cells of normal oral epithelium and suppresses keratinocyte differentiation. Our previous study indicated that up-regulation of KLF5 in combination with KLF4 down-regulation induces the epithelial-mesenchymal transition of oral carcinoma cells. Although transcriptional regulation of KLF4 is documented previously, nothing is known about KLF5 transcription.
Methods: In the present study, we ligated KLF5 promoter (-2,001 to +424) and the shorter into Luc-reporter plasmids and transfected them into HEK293T cells and HSC2 cells. Twenty-four hours after the transfection, Luc activities in total protein lysate normalized by hRluc were measured (n=4).
Results: Analogous results were obtained in HEK293T cells and HSC2 cells; the Luc activity of the -1,576 to +424 construct was significantly higher than that of the -2,001 full-length construct. Deletion of 99 bp from +145 significantly decreased the activities.
Conclusions: These date indicate that the up-stream region between -2,001 and -1,576 contains transcription repressor region for KLF5 gene and that the +145 to +243 region contains a minimal essential element for the transcription.