Bhaskar Vinay, Courey Albert J
Department of Chemistry and Biochemistry, University of California-Los Angeles, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569, USA.
Gene. 2002 Oct 16;299(1-2):173-84. doi: 10.1016/s0378-1119(02)01058-2.
The transcription factors Dorsal and Twist regulate dorsoventral axis formation during Drosophila embryogenesis. Dorsal and Twist bind to closely linked DNA elements in a number of promoters and synergistically activate transcription. We have identified a novel protein named Dorsal-interacting protein 3 (Dip3) that may play a role in this synergy. Dip3 functions as a coactivator to stimulate synergistic activation by Dorsal and Twist, but does not stimulate simple activation of promoters containing only Dorsal or only Twist binding sites. In addition, Dip3 is able to bind DNA in a sequence specific manner and activate transcription directly. Dip3 possesses an N-terminal MADF domain and a C-terminal BESS domain, an architecture that is conserved in at least 14 Drosophila proteins, including Adf-1 and Stonewall. The MADF domain directs sequence specific DNA binding to a site consisting of multiple trinucleotide repeats, while the BESS domain directs a variety of protein-protein interactions, including interactions with itself, with Dorsal, and with a TBP-associated factor. We assess the possibility that the MADF and BESS domains are related to the SANT domain, a well-characterized motif found in many transcriptional regulators and coregulators.
转录因子背腹蛋白（Dorsal）和扭转蛋白（Twist）在果蝇胚胎发育过程中调节背腹轴的形成。背腹蛋白和扭转蛋白与许多启动子中紧密相连的DNA元件结合，并协同激活转录。我们鉴定出一种名为背腹相互作用蛋白3（Dip3）的新蛋白，它可能在这种协同作用中发挥作用。Dip3作为一种共激活因子，刺激背腹蛋白和扭转蛋白的协同激活，但不刺激仅含有背腹蛋白或仅含有扭转蛋白结合位点的启动子的简单激活。此外，Dip3能够以序列特异性方式结合DNA并直接激活转录。Dip3具有一个N端MADF结构域和一个C端BESS结构域，这种结构在至少14种果蝇蛋白中是保守的，包括Adf-1和石墙蛋白（Stonewall）。MADF结构域指导序列特异性DNA与由多个三核苷酸重复组成的位点结合，而BESS结构域指导多种蛋白质-蛋白质相互作用，包括与自身、与背腹蛋白以及与一种TBP相关因子的相互作用。我们评估了MADF和BESS结构域与SANT结构域相关的可能性，SANT结构域是在许多转录调节因子和共调节因子中发现的一种特征明确的基序。
