Department of Biology, Emory University, Atlanta, GA 30322, USA.
Mol Cell. 2011 Oct 7;44(1):29-38. doi: 10.1016/j.molcel.2011.07.035.
Insulators are multiprotein-DNA complexes thought to affect gene expression by mediating inter- and intrachromosomal interactions. Drosophila insulators contain specific DNA-binding proteins plus common components, such as CP190, that facilitate these interactions. Here, we examine changes in the distribution of Drosophila insulator proteins during the heat-shock and ecdysone responses. We find that CP190 recruitment to insulator sites is the main regulatable step in controlling insulator function during heat shock. In contrast, both CP190 and DNA-binding protein recruitment are regulated during the ecdysone response. CP190 is necessary to stabilize specific chromatin loops and for proper activation of transcription of genes regulated by this hormone. These findings suggest that cells may regulate recruitment of insulator proteins to DNA to activate insulator activity at specific sites and create distinct patterns of nuclear organization that are necessary to achieve proper gene expression in response to different stimuli.
绝缘子是多蛋白-DNA 复合物，被认为通过介导染色体间和染色体内相互作用来影响基因表达。果蝇绝缘子包含特定的 DNA 结合蛋白和常见的成分，如 CP190，这些成分有助于这些相互作用。在这里，我们研究了果蝇绝缘子蛋白在热激和蜕皮激素反应过程中的分布变化。我们发现，CP190 募集到绝缘子位点是控制热激期间绝缘子功能的主要可调节步骤。相比之下，CP190 和 DNA 结合蛋白的募集在蜕皮激素反应过程中都受到调节。CP190 对于稳定特定的染色质环以及正确激活受该激素调控的基因的转录是必需的。这些发现表明，细胞可能通过调节绝缘子蛋白与 DNA 的募集来激活特定位点的绝缘子活性，并创建不同的核组织模式，这对于响应不同刺激实现适当的基因表达是必要的。
