Decoville M, Giraud-Panis M J, Mosrin-Huaman C, Leng M, Locker D
Centre de Biophysique Moléculaire, CNRS, conventionné avec l'Université d'Orléans, rue Charles Sadron, 45071 Orléans cedex 2, France.
Nucleic Acids Res. 2000 Jan 15;28(2):454-62. doi: 10.1093/nar/28.2.454.
Formation of the dorsoventral axis in Drosophila melanogaster is mediated through control of the expression of several genes by the morphogen Dorsal. In the ventral part of the embryo Dorsal activates twist and represses zen amongst others. Recently, several proteins have been shown to assist Dorsal in the repression of zen, one of which is DSP1, a HMG box protein that was isolated as a putative co-repressor of Dorsal. In this report we used a DSP1 null mutant to ascertain in vivo the involvement of DSP1 in Dorsal-mediated repression of zen but not in the activation of twist. We show that Dorsal has the ability to interact with DSP1 in vitro as well as with rat HMG1. Using truncated versions of the proteins we located the domains of interaction as being the HMG boxes for DSP1 and HMG1 and the Rel domain for Dorsal. Finally, studies of the zen DNA binding properties of Dorsal and another related Rel protein (Gambif1 from Anopheles gambiae) revealed that their DNA binding affinities were increased in the presence of DSP1 and HMG1.
果蝇背腹轴的形成是通过形态发生素背蛋白（Dorsal）对多个基因表达的调控来介导的。在胚胎的腹侧部分，背蛋白激活扭曲基因（twist）并抑制例如锌指蛋白基因（zen）等基因。最近，已证明几种蛋白质协助背蛋白抑制锌指蛋白基因，其中之一是DSP1，一种作为背蛋白假定共抑制因子分离出来的HMG盒蛋白。在本报告中，我们使用DSP1基因敲除突变体在体内确定DSP1参与背蛋白介导的锌指蛋白基因抑制，但不参与扭曲基因的激活。我们表明，背蛋白在体外既能与DSP1相互作用，也能与大鼠HMG1相互作用。使用蛋白质的截短版本，我们确定相互作用的结构域为DSP1和HMG1的HMG盒以及背蛋白的Rel结构域。最后，对背蛋白和另一种相关Rel蛋白（冈比亚按蚊的Gambif1）与锌指蛋白基因DNA结合特性的研究表明，在DSP1和HMG1存在的情况下，它们与DNA的结合亲和力增加。
