Parker C S, Topol J
Cell. 1984 Feb;36(2):357-69. doi: 10.1016/0092-8674(84)90229-0.
Drosophila RNA polymerase II requires at least two chromatographically distinct transcription factors (designated A and B) to initiate transcription accurately in vitro. We describe the partial purification and concentration of one of these transcription factors, the B factor. Footprint analysis of the B fraction demonstrated the presence of a sequence-specific DNA-binding component in the transcription factor preparation. This component binds specifically to a 65 bp region of DNA surrounding the start point of transcription of the histone H3, H4, and actin 5C genes. Included in this binding region is the TATA box, the start point of transcription, and a portion of the leader region. The pattern of protection from DNAase I cleavage on the coding strand of the histone H3 gene is asymmetric with regard to the complementary noncoding strand. Sequence-specific binding of the B fraction occurs in the apparent absence of RNA polymerase II. The potential function of the binding component in the initiation of transcription by RNA polymerase II is discussed.
果蝇RNA聚合酶II在体外准确启动转录至少需要两种色谱性质不同的转录因子（分别命名为A和B）。我们描述了其中一种转录因子B因子的部分纯化和浓缩过程。对B组分的足迹分析表明，转录因子制剂中存在一种序列特异性DNA结合成分。该成分特异性结合围绕组蛋白H3、H4和肌动蛋白5C基因转录起始点的65 bp DNA区域。该结合区域包括TATA框、转录起始点和部分前导区域。组蛋白H3基因编码链上对DNA酶I切割的保护模式相对于互补的非编码链是不对称的。B组分的序列特异性结合在明显不存在RNA聚合酶II的情况下发生。讨论了结合成分在RNA聚合酶II启动转录中的潜在功能。
