Zheng X M, Black D, Chambon P, Egly J M
Laboratoire de Génétique Moléculaire des Eucaryotes du CNRS, Unité 184 de Biologie Moléculaire et de Génie Génétique de L'INSERM, Faculté de Médecine, Strasbourg, France.
Nature. 1990 Apr 5;344(6266):556-9. doi: 10.1038/344556a0.
The initiation of transcription of eukaryotic genes involves the ordered assembly of a multiprotein complex on proximal promoter elements such as the TATA box. In addition to RNA polymerase II (otherwise RNA pol II, RNA polymerase B), four general transcription factors are required for initiation of transcription: BTF1 (also referred to as TFIID) which has recently been cloned from yeast, BTF2, BTF3 and STF. The first step in assembly of the initiation complex is the stable binding of BTF1 to the TATA box, which is facilitated by STF. Neither BTF2 nor BTF3 bind directly to the promoter proximal elements, but BTF3 can form a stable complex with RNA pol II. We recently purified BTF3, which is a protein of relative molecular mass 27,000, but further studies have been hampered by its low abundance in cells. On the basis of sequences from peptides of BTF3, we have now cloned two complementary DNAs, one for a protein (BTF3a) with all the characteristics of purified BTF3, and one for a shorter protein (BTF3b) lacking the first 44 residues of BTF3a and which is transcriptionally inactive, despite its ability to bind RNA pol II.
真核基因转录的起始涉及在近端启动子元件（如TATA盒）上有序组装多蛋白复合物。除了RNA聚合酶II（也称为RNA pol II、RNA聚合酶B）外，转录起始还需要四种通用转录因子：最近从酵母中克隆出来的BTF1（也称为TFIID）、BTF2、BTF3和STF。起始复合物组装的第一步是BTF1与TATA盒的稳定结合，这由STF促进。BTF2和BTF3都不直接与启动子近端元件结合，但BTF3可以与RNA pol II形成稳定复合物。我们最近纯化了BTF3，它是一种相对分子质量为27000的蛋白质，但由于其在细胞中的丰度较低，进一步的研究受到了阻碍。基于BTF3肽段的序列，我们现在克隆了两个互补DNA，一个对应具有纯化BTF3所有特征的蛋白质（BTF3a），另一个对应缺少BTF3a前44个残基的较短蛋白质（BTF3b），尽管它能够结合RNA pol II，但转录无活性。
