Transcriptional regulation of the 5'-flanking region of the human transcription factor Sp3 gene by NF-1, c-Myb, B-Myb, AP-1 and E2F.
We analyzed in detail the proximal promoter of transcription factor Sp3, which expands 281 bp from the translational start. This sequence contains putative binding sites for Sp1, NF-Y, NF-1, Myb, AP-1 and E2F transcription factors. In this work, we further explored the role of these boxes on the regulation of the Sp3 gene. Gel-shift and competition assays showed specific binding of NF-1, Myb, AP-1 and E2F. Furthermore, chromatin immunoprecipitation assays demonstrated that Sp1, Sp3, NF-Y, NF-1, c-Myb, B-Myb, c-Jun and E2F1 actually occupied the Sp3 promoter in HeLa cells. Transient transfections and luciferase assays revealed activation of the Sp3 proximal promoter upon overexpression of NF-1, c-Myb, B-Myb, c-Jun and c-Fos, and repression after overexpression of E2F/DP1. Point mutation of the binding sites for NF1, Myb, AP1 and E2F and cell incubation with specific siRNAs further confirmed the role of these transcription factors in the regulation of the Sp3 promoter. The regulation of the endogenous Sp3 gene was also observed at the mRNA level when the studied transcription factors were overexpressed or knocked down by siRNA incubation. These results help to explain the complex regulation of the Sp3 gene, which depends, at least in part, on the relative amount of Sp1, Sp3, NF-Y, NF-1, c-Myb, B-Myb, AP-1, and E2F proteins in the cell.
Tapias
Alicia
A
Department of Biochemistry and Molecular Biology, School of Pharmacy, IBUB, University of Barcelona, Av. Diagonal 643, E-08028, Barcelona, Spain.
Ciudad
Carlos J
CJ
Noé
Véronique
V
D024506:5' Flanking Region; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D050684:E2F Transcription Factors / Q000378:metabolism; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D025542:Neurofibromin 1 / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism; D051703:Sp Transcription Factors / Q000378:metabolism; D051705:Sp3 Transcription Factor / Q000235:genetics*; D015534:Trans-Activators / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D018797:Cell Cycle Proteins; D050684:E2F Transcription Factors; C064352:MYBL2 protein, human; D025542:Neurofibromin 1; D020598:Proto-Oncogene Proteins c-myb; C497121:SP3 protein, human; D051703:Sp Transcription Factors; D015534:Trans-Activators; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D051705:Sp3 Transcription Factor