O'Donnell K H, Wensink P C
Department of Biochemistry, Brandeis University, Waltham, MA 02254-9110.
Nucleic Acids Res. 1994 Nov 11;22(22):4712-8. doi: 10.1093/nar/22.22.4712.
Three DNA regions (TE1, TE2 and the intron) regulate the ubiquitous expression of the alpha 1-tubulin gene of Drosophila melanogaster. In this report, we identify two proteins that bind these DNA regions. One is the previously characterized GAGA transcription factor and the other is a newly identified 62 kDa polypeptide, TBF1 (TE1-binding factor 1). Purified GAGA factor binds three sites in TE2 and at least three in the intron. TBF1 was purified from embryos and binds to both TE1 and TE2. Together, the two proteins produce the same DNase I footprints in TE1 and TE2 as does a nuclear extract that transcribes the gene accurately. These footprints cover most of the TE1 and TE2 DNA. Moreover, one binding site for each protein coincides with a site that activates transcription in vitro. The characteristics of the GAGA factor and the genes it regulates suggest roles these two proteins are likely to play in regulating ubiquitous expression.
三个DNA区域（TE1、TE2和内含子）调控果蝇α1 - 微管蛋白基因的普遍表达。在本报告中，我们鉴定出两种与这些DNA区域结合的蛋白质。一种是先前已表征的GAGA转录因子，另一种是新鉴定出的62 kDa多肽，即TBF1（TE1结合因子1）。纯化的GAGA因子结合TE2中的三个位点以及内含子中的至少三个位点。TBF1是从胚胎中纯化出来的，它能与TE1和TE2结合。这两种蛋白质共同作用，在TE1和TE2中产生的DNase I足迹与能够精确转录该基因的核提取物所产生的足迹相同。这些足迹覆盖了大部分TE1和TE2 DNA。此外，每种蛋白质的一个结合位点与体外激活转录的位点重合。GAGA因子及其调控的基因的特性表明这两种蛋白质在调控普遍表达中可能发挥的作用。
