The binding site for the liver-specific transcription factor Tf-LF1 and the TATA box of the human transferrin gene promoter are the only elements necessary to direct liver-specific transcription in vitro.
We have studied the liver-specific transcriptional activity of the human transferrin gene promoter. Results of competition experiments, site-directed mutagenesis, and 5' deletion analysis have demonstrated that a TATA box and a binding site for the liver-specific protein Tf-LF1 are the only elements needed to direct hepatic-specific transcription in vitro. Thus, Tf-LF1 behaves as other previously described proteins, HNF-1, DBP and LF-A1, in that it is sufficient to confer liver-specific transcriptional activity to a promoter in vitro. This results contrast with observations made in transient expression experiments, in which Tf-LF1 binding alone cannot direct hepatic-specific expression, and the binding of at least one more protein, similar to C/EBP, is needed. Thus, as described for other hepatic genes, the number of elements necessary to confer tissue specificity is different in vivo and in vitro.
Mendelzon
D
D
Laboratoire d'Expression des Gènes Eucaryotes, Institut Pasteur, Paris, France.
Boissier
F
F
Zakin
M M
MM
D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D005796:Genes; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009928:Organ Specificity / Q000235:genetics; D011401:Promoter Regions, Genetic; D016385:TATA Box; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014168:Transferrin / Q000235:genetics*
D014157:Transcription Factors; D014168:Transferrin