Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
EMBO Rep. 2013 Oct;14(10):916-22. doi: 10.1038/embor.2013.118. Epub 2013 Aug 6.
Chromatin insulators are DNA protein complexes situated throughout the genome capable of demarcating independent transcriptional domains. Previous studies point to an important role for RNA in gypsy chromatin insulator function in Drosophila; however, the identity of these putative insulator-associated RNAs is not currently known. Here we utilize RNA-immunoprecipitation and high throughput sequencing (RIP-seq) to isolate RNAs stably associated with gypsy insulator complexes. Strikingly, these RNAs correspond to specific sense-strand, spliced and polyadenylated mRNAs, including two insulator protein transcripts. In order to assess the functional significance of these associated mRNAs independent of their coding function, we expressed untranslatable versions of these transcripts in developing flies and observed both alteration of insulator complex nuclear localization as well as improvement of enhancer-blocking activity. Together, these data suggest a novel, noncoding mechanism by which certain mRNAs contribute to chromatin insulator function.
染色质绝缘子是遍布基因组的 DNA 蛋白复合物，能够划分独立的转录结构域。先前的研究表明，RNA 在果蝇中的 gypsy 染色质绝缘子功能中起着重要作用；然而，这些假定的绝缘子相关 RNA 的身份目前尚不清楚。在这里，我们利用 RNA 免疫沉淀和高通量测序（RIP-seq）来分离与 gypsy 绝缘子复合物稳定相关的 RNA。引人注目的是，这些 RNA 对应于特定的有义链、拼接和多聚腺苷酸化的 mRNA，包括两个绝缘子蛋白转录本。为了评估这些相关 mRNA 的功能意义，而不考虑其编码功能，我们在发育中的果蝇中表达了这些转录本的无翻译版本，并观察到绝缘子复合物核定位的改变以及增强子阻断活性的提高。总之，这些数据表明，某些 mRNA 通过一种新的非编码机制来促进染色质绝缘子功能。
