Alvarez Martinez Cristina E, Binato Renata, Gonzalez Sayonara, Pereira Monica, Robert Benoit, Abdelhay Eliana
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Biochem Biophys Res Commun. 2002 Mar 1;291(3):655-62. doi: 10.1006/bbrc.2002.6502.
Mouse Msx 1 gene, orthologous of the Drosophila msh, is involved in several developmental processes. BMP family members are major proteins in the regulation of Msx 1 expression. BMP signaling activates Smad 1/5/8 proteins, which associate to Smad 4 before translocating to the nucleus. Analysis of Msx 1 promoter revealed the presence of three elements similar to the consensus established for Mad, the Smad 1 Drosophila counterpart. Notably, such an element was identified in an enhancer important for Msx 1 regulation. Gel shift analysis demonstrated that proteins from 13.5 dpc embryo associate to this enhancer. Remarkably, supershift assays showed that Smad proteins are present in the complex. Purified Smad 1 and 4 also bind to this fragment. We demonstrate that functional binding sites in this enhancer are confined to the Mad motif and flanking region. Our data suggest that this Mad motif may be functional in response to BMP signaling.
小鼠Msx 1基因是果蝇msh的直系同源基因，参与多个发育过程。骨形态发生蛋白（BMP）家族成员是调控Msx 1表达的主要蛋白质。BMP信号激活Smad 1/5/8蛋白，这些蛋白在转运至细胞核之前与Smad 4结合。对Msx 1启动子的分析显示存在三个与为Mad（果蝇中的Smad 1对应物）建立的共有序列相似的元件。值得注意的是，在对Msx 1调控很重要的一个增强子中鉴定出了这样一个元件。凝胶迁移分析表明来自13.5天胚胎的蛋白质与该增强子结合。显著的是，超迁移分析显示该复合物中存在Smad蛋白。纯化的Smad 1和Smad 4也与该片段结合。我们证明该增强子中的功能性结合位点局限于Mad基序及其侧翼区域。我们的数据表明该Mad基序可能在响应BMP信号时发挥功能。
