|Reference : A TEF-1 binding motif that interacts with a placental protein is important for the tr...|
|Scientific journals : Article|
|Life sciences : Biochemistry, biophysics & molecular biology|
|A TEF-1 binding motif that interacts with a placental protein is important for the transcriptional activity of the hCS-B enhancer|
|Jacquemin, P. [> > > >]|
|Oury, Cécile [Université de Liège - ULg > Département des sciences biomédicales et précliniques > GIGA-R : Génétique générale et humaine >]|
|Belayew, A. [> > > >]|
|Martial, Joseph [Université de Liège - ULg > Département des sciences de la vie > GIGA-R : Biologie et génétique moléculaire >]|
|DNA & Cell Biology|
|Mary Ann Liebert, Inc.|
|Yes (verified by ORBi)|
|[en] Base Sequence ; Cell Line ; DNA-Binding Proteins/*metabolism ; *Enhancer Elements, Genetic ; Hela Cells ; Humans ; Molecular Sequence Data ; Molecular Weight ; Nuclear Proteins/*metabolism ; Oligodeoxyribonucleotides ; Peptides/metabolism ; Placental Lactogen/*genetics/metabolism ; Point Mutation ; Protein Binding ; Transcription Factors/*metabolism|
|[en] The transcriptional activity of the human placental lactogen genes (choriosomatomammotropic hormone, hCS) is controlled by tissue-specific enhancers located 4 kb downstream from their respective origins of transcription. The hCS-B enhancer is the strongest; its activity is mediated by synergism between two protein-binding sites (DF-3 and DF-4). The DF-4 site possesses a potential binding sequence for TEF-1, a known transcription factor. In this paper, we show by electrophoretic mobility-shift assays and antibody supershift experiments that TEF-1 does not bind to site DF-4. Mutations in the TEF-1-like binding motif of site DF-4 prevent formation of the DNA-protein complex, called complex f, in the presence of placental JEG-3 cell extracts. When HeLa cell extracts are used, another complex (complex c) is also affected. In transient expression experiments, TKCAT constructs linked to this mutated DF-4 site exhibit greatly reduced transcriptional activity when introduced into JEG-3 cells. Some cell lines contain both protein c and protein f (the proteins forming complexes c and f); when transfected, these lines display reduced DF-4-driven activity, suggesting that the two proteins could compete for the same DF-4 sequence. We conclude that protein f is important for the placenta-specific activity of the hCS-B enhancer. By UV cross-linking, we show that protein f is actually three polypeptides ranging in size from about 12 to 21 kD.|
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