多梳组突变 esc 导致果蝇胚胎中暂停的 Pol II 水平升高。
The polycomb group mutant esc leads to augmented levels of paused Pol II in the Drosophila embryo.
机构信息
Department of Molecular and Cell Biology, Division of Genetics, Genomics, and Development, University of California, Berkeley, Berkeley, CA 94720, USA.
出版信息
Mol Cell. 2011 Jun 24;42(6):837-44. doi: 10.1016/j.molcel.2011.05.009.
Many developmental control genes contain paused RNA polymerase II (Pol II) and are thereby "poised" for rapid and synchronous activation in the early Drosophila embryo. Evidence is presented that Polycomb group (PcG) repressors can influence paused Pol II. ChIP-Seq and GRO-Seq assays were used to determine the genome-wide distributions of Pol II, H3K27me3, and H3K4me3 in extra sex combs (esc) mutant embryos. ESC is a key component of the Polycomb repressive complex 2 (PRC2), which mediates H3K27me3 modification. Enhanced Pol II occupancy is observed for thousands of genes in esc mutant embryos, including genes not directly regulated by PRC2. Thus, it would appear that silent genes lacking promoter-associated paused Pol II in wild-type embryos are converted into "poised" genes with paused Pol II in esc mutants. We suggest that this conversion of silent genes into poised genes might render differentiated cell types susceptible to switches in identity in PcG mutants.
许多发育控制基因包含暂停的 RNA 聚合酶 II（Pol II），因此在早期果蝇胚胎中处于快速和同步激活的“准备”状态。有证据表明，多梳组（PcG）抑制剂可以影响暂停的 Pol II。使用 ChIP-Seq 和 GRO-Seq 测定法来确定 Pol II、H3K27me3 和 H3K4me3 在额外性梳（esc）突变体胚胎中的全基因组分布。ESC 是多梳抑制复合物 2（PRC2）的关键组成部分，介导 H3K27me3 修饰。在 esc 突变体胚胎中观察到数千个基因的增强 Pol II 占据，包括不受 PRC2 直接调节的基因。因此，似乎在野生型胚胎中缺乏启动子相关暂停 Pol II 的沉默基因被转化为在 esc 突变体中具有暂停 Pol II 的“准备”基因。我们认为，这种沉默基因转化为有潜力的基因可能使分化的细胞类型容易受到 PcG 突变体中身份转变的影响。
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