Different Sp1 family members differentially affect transcription from the human elongation factor 1 A-1 gene promoter.
The GC box is an important transcriptional regulatory element present in the promoters of many mammalian genes. In the present study we examine the effect of known GC-box-binding proteins on the promoter of the human elongation factor 1 A-1 (hEF1A-1) gene in human HeLa cells and Drosophila SL2 cells. In HeLa cells co-transfection with the GC-box-binding protein BTEB resulted in a 4-10-fold increase in hEF1A-1 promoter activity. This stimulation was dependent on a single GC box located between positions -69 and -50 of the promoter. Little or no effect was observed of other GC-box-binding proteins including Sp1, Sp3, Sp4 and BTEB2. In SL2 cells stimulation by Sp1 and Sp3 through the single GC box of the proximal promoter led to 13-fold and 21-fold increases respectively in promoter activity. Inclusion of further upstream sequences resulted in high levels of expression when Sp1 or Sp3 was co-transfected with the reporter plasmid. In this setting Sp1 stimulated transcription by 750-fold, whereas Sp3 was even more potent, yielding a 1150-fold stimulation. Mobility-shift assays performed with the promoter-proximal GC box demonstrated the binding of Sp1, Sp3 and Sp4 to this sequence. To our knowledge, the present study represents the first comparison of all known GC-box-binding proteins on a natural promoter.
Department of Biostructural Chemistry, Institute of Molecular and Structural Biology, University of Aarhus, Gustav Wieds Vej 10C, Forskerparken, Arhus, Denmark.
S J
SJ
Nielsen
M
M
Praestegaard
H F
HF
Jorgensen
B F
BF
Clark
D000818:Animals; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology*; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology*; D015533:Transcriptional Activation / Q000502:physiology; D014162:Transfection
D004268:DNA-Binding Proteins; C489676:KLF9 protein, human; D051741:Kruppel-Like Transcription Factors; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D016329:Sp1 Transcription Factor; D014157:Transcription Factors