Ohtsuki S, Levine M
Department of Molecular and Cellular Biology, Division of Genetics, University of California at Berkeley, Berkeley, California 94720 USA.
Genes Dev. 1998 Nov 1;12(21):3325-30. doi: 10.1101/gad.12.21.3325.
Insulator DNAs and promoter competition regulate enhancer-promoter interactions within complex genetic loci. A transgenic embryo assay was used to obtain evidence that the Drosophila eve promoter possesses an insulator activity that can be uncoupled from the core elements that mediate competition. The eve promoter contains an optimal TATA element and a GAGA sequence. The analysis of various chimeric promoters provides evidence that TATA is essential for promoter competition, whereas GAGA mediates enhancer blocking. The Trithorax-like (Trl) protein interacts with GAGA, and mutations in trl attenuate eve promoter insulator activity. We suggest that Trl-GAGA increases the stability of enhancer-promoter interactions by creating an open chromatin configuration at the core promoter.
绝缘子DNA与启动子竞争调控复杂基因座内的增强子-启动子相互作用。利用转基因胚胎试验获得证据，表明果蝇eve启动子具有一种绝缘子活性，该活性可与介导竞争的核心元件解偶联。eve启动子包含一个最佳的TATA元件和一个GAGA序列。对各种嵌合启动子的分析提供了证据，表明TATA对于启动子竞争至关重要，而GAGA介导增强子阻断。类三体胸蛋白（Trl）与GAGA相互作用，trl中的突变会减弱eve启动子的绝缘子活性。我们认为，Trl-GAGA通过在核心启动子处形成开放染色质构型来增加增强子-启动子相互作用的稳定性。
