Transcription factors of the Sp1 family: interaction with E2F and regulation of the murine thymidine kinase promoter.
Promoters of growth and cell cycle regulated genes frequently carry binding sites for transcription factors of the E2F and Sp1 families. We have demonstrated recently that direct interaction between Sp1 and a subgroup of the E2F factors is essential for the regulation of certain promoters. We show here that the amino acids necessary for this interaction in both cases are located within the DNA binding domain. This is in line with the assumption, that the interaction between E2F and Sp-factors contributes to promoter-specificity. Cyclin A, which binds to E2F-1 in close vicinity to Sp1 does not interfere with this interaction. Moreover we have investigated the ability of other members of the Sp1 family to interact with E2F-1 and to regulate the activity of the E2F and Sp1 dependent murine thymidine kinase promoter. All four factors of the Sp1 family are able to bind E2F-1 in co-immunoprecipitation and GST-pull down experiments. Mobility shift assays with oligonucleotides comprising the Sp1, or both the Sp1 and the E2F binding site suggest that Sp1 and Sp3 supply most if not all activity binding to the GC-box of the thymidine kinase promoter in murine fibroblasts. Reporter gene assays in Drosophila melanogaster SL2 cells and murine fibroblast 3T6 cells demonstrate that the thymidine kinase promoter is activated strongly by Sp1 and Sp3, weakly by Sp4, and not at all by Sp2. Co-expression of E2F-1 results in synergistic activation in 3T6 but not in SL2 cells.
Rotheneder
H
H
Vienna Biocenter, University of Vienna, Austria. jr@mol.univie.ac.at
Geymayer
S
S
Haidweger
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002460:Cell Line; D019925:Cyclin A / Q000378:metabolism / Q000494:pharmacology; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D005347:Fibroblasts; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D056465:Retinoblastoma-Binding Protein 1; D016415:Sequence Alignment; D017384:Sequence Deletion; D016329:Sp1 Transcription Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013937:Thymidine Kinase / Q000235:genetics*; D015534:Trans-Activators; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
C533431:Arid4a protein, mouse; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D019925:Cyclin A; D004268:DNA-Binding Proteins; C088053:Dp transcription factor, Drosophila; D029721:Drosophila Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493754:E2f1 protein, mouse; D011993:Recombinant Fusion Proteins; D056465:Retinoblastoma-Binding Protein 1; D016329:Sp1 Transcription Factor; D015534:Trans-Activators; D050680:Transcription Factor DP1; D014157:Transcription Factors; D004247:DNA; D013937:Thymidine Kinase