Mendelzon D, Boissier F, Zakin M M
Laboratoire d'Expression des Gènes Eucaryotes, Institut Pasteur, Paris, France.
Nucleic Acids Res. 1990 Oct 11;18(19):5717-21. doi: 10.1093/nar/18.19.5717.
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.
我们研究了人转铁蛋白基因启动子的肝脏特异性转录活性。竞争实验、定点诱变和5'缺失分析的结果表明，TATA盒和肝脏特异性蛋白Tf-LF1的结合位点是体外指导肝脏特异性转录所需的唯一元件。因此，Tf-LF1的作用与先前描述的其他蛋白质HNF-1、DBP和LF-A1相同，即它足以在体外赋予启动子肝脏特异性转录活性。这些结果与瞬时表达实验中的观察结果形成对比，在瞬时表达实验中，仅Tf-LF1结合不能指导肝脏特异性表达，还需要至少一种与C/EBP相似的蛋白质结合。因此，正如对其他肝脏基因所描述的那样，赋予组织特异性所需的元件数量在体内和体外是不同的。
