生物通报道：细胞分化过程中，干细胞激活各种基因表达需要反式作用因子（trans-acting factors）聚集在增强子和启动子周围。

伦敦帝国大学医学系和法国IGBMC（Institut de Genetique et de Biologie Moleculaire et Cellulaire）研究所研究人员发现，蛋白酶体（proteasome）作用于胚胎干细胞（embryonic stem ，ES） 的特异调节区域，防止不正确的转录。用化学法或siRNA抑制蛋白酶体活性，导致转录因子水平上升，RNA聚合酶II结合并激活隐秘的（crypti）启动子。研究人员分析正常ES细胞中蛋白酶体各个亚基的结合特征，随后依次用RNAi沉默各个亚基，进一步证明26S蛋白酶体聚集于特异调节元件的附近区域。

研究结果提示ES细胞中，蛋白酶体促进转录因子的动力周转，促进Pol II 与组织特异基因区域结合，以控制获许可的转录活动并维持基因处于增强状态，为稍后的激活作好准备。（生物通记者 小粥）

原文：

The ability of stem cells to activate different gene expression programs requires the choreographed assembly of trans-acting factors at enhancers and promoters during cell differentiation. In this study, we show that the proteasome acts on specific regulatory regions in embryonic stem (ES) cells to prevent incorrect transcriptional initiation. Chemical or siRNA-mediated inhibition of proteasome activity results in increased transcription factor and RNA polymerase II binding and leads to activation of cryptic promoters. Analysis of the binding profiles of different proteasome subunits in normal ES cells and following RNAi knockdown of individual subunits provides evidence for a targeted assembly of the 26S proteasome at specific regulatory elements. Our results suggest that the proteasome promotes a dynamic turnover of transcription factor and Pol II binding at tissue-specific gene domains in ES cells, thereby restricting permissive transcriptional activity and keeping the genes in a potentiated state, ready for activation at later stages.