Georgel P, Dretzen G, Jagla K, Bellard F, Dubrovsky E, Calco V, Bellard M
Laboratoire de Génétique Moléculaire des Eucaryotes du CNRS, Institut de Chimie Biologique, Faculté de Médecine, Strasbourg, France.
J Mol Biol. 1993 Nov 20;234(2):319-30. doi: 10.1006/jmbi.1993.1589.
The enhancer region of the Drosophila melanogaster ecdysone-regulated glue gene, Sgs3, shows dramatic modifications of chromatin structure in strict correlation with changes in gene expression during development. We show that there is a positioned nucleosomal core particle over the enhancer which is displaced or disrupted during gene activation. This transition is prevented in Drosophila larvae mutated in the ecdysone-dependent 2B5 locus, in which Sgs3 is inactive and GEBF-I, a Glue Enhancer Binding Factor, is missing. We have defined the GEBF-I binding sites in vitro and shown that mutation of these sequences abolishes the enhancer activity in vivo. This combined in vitro and in vivo approach reveals new aspects of the dynamic organization of a regulatory element during development and highlights the potential of this model for studies of the relation between chromatin structure and gene activity.
果蝇黑腹果蝇蜕皮激素调节的胶水基因Sgs3的增强子区域显示出染色质结构的显著修饰，与发育过程中基因表达的变化严格相关。我们发现，在增强子上有一个定位的核小体核心颗粒，在基因激活过程中它会被取代或破坏。在蜕皮激素依赖性2B5位点发生突变的果蝇幼虫中，这种转变被阻止，在这些幼虫中Sgs3无活性且缺少胶水增强子结合因子GEBF-I。我们已经在体外确定了GEBF-I的结合位点，并表明这些序列的突变会消除体内的增强子活性。这种体外和体内相结合的方法揭示了发育过程中调控元件动态组织的新方面，并突出了该模型在研究染色质结构与基因活性之间关系方面的潜力。
