A critical role of Sp1 transcription factor in regulating the human Ki-67 gene expression

Abstract

Objective To investigate the critical role of Sp1 transcription factor in regulating the human Ki-67 gene expression.Methods The Sp1 expression vector pN3-Sp1 was transfected into Hela cells,OS-RC-2 cells and A549 cells.Immunoblotting assay was performed to detect the change of Sp1 protein in Hela cells.Immunohistochemistry was performed to detect the change of Ki-67 protein in Hela cells,OS-RC-2 cells and A549 cells.Finally using the dual-luciferase reporter assay system to identify the difference of transcriptional activity between pN3-Sp1 plasmid and the pN3-Sp1 plasmid with Ki-67 promoter plasmid pGLBK23 cotransfection.Results After transfected by pN3-Sp1,the protein of Sp1 in Hela cells and Ki-67 protein in Hela cells,OS-RC-2 cells and A549 cells were increased.The transcriptional activities of plasmid pGLBK235 that was co-transfected with pN3-Sp1 also increased.The transcriptional activities in Hela cells,OS-RC-2 cells and A549 cells cotransfected with pN3-Sp1 and pGLBK235 plasmid exhibited transcriptional activities respectively equivalent to 1.68-fold,1.34-fold and 1.83-fold of pGLBK235 transfected.Conclusion The overexpression of Sp1 can increase the transcriptional activity of Ki-67 by raising the expression of Sp1 protein.The transcription factor Sp1 can positively regulate the transcription of Ki-67 gene. Key words: Ki-67 promoter; Transcription factors Sp1