Transcription of bxd noncoding RNAs promoted by trithorax represses Ubx in cis by transcriptional interference
Transcription of bxd noncoding RNAs promoted by trithorax represses Ubx in cis by transcriptional interference
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DOI：
10.1016/j.cell.2006.10.039
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发表时间：
2006-12-15
期刊：
影响因子：
64.5
通讯作者：
Mazo, Alexander
中科院分区：
文献类型：
--
作者：
Petruk, Svetlana;Sedkov, Yurii;Mazo, Alexander
基因组的大部分被转录成长非编码RNA（ncRNA）。先前的数据表明，果蝇双胸复合体（BX-C）的双胸类（bxd）ncRNA防止超双胸（Ubx）的沉默，并将三胸组（trxG）的活化蛋白募集到其维持元件（ME）。我们发现，令人惊讶的是，Ubx和几个bxd ncRNA在胚胎和成虫盘中以非重叠模式表达，这表明这些ncRNA的转录与Ubx的抑制有关，而不是激活。我们的数据排除了基于siRNA或miRNA的bxd ncRNA抑制机制。相反，ncRNA转录本身以顺式作用，抑制Ubx。三胸复合物TAC 1结合表达Ubx的细胞核中的Ubx编码区，和不表达Ubx的细胞核中的bxd区。我们建议，TAC 1促进嵌合模式的Ubx表达，促进转录延长bxd ncRNA，抑制Ubx转录。
Much of the genome is transcribed into long noncoding RNAs (ncRNAs). Previous data suggested that bithoraxoid (bxd) ncRNAs of the Drosophila bithorax complex (BX-C) prevent silencing of Ultrabithorax (Ubx) and recruit activating proteins of the trithorax group (trxG) to their maintenance elements (MEs). We found that, surprisingly, Ubx and several bxd ncRNAs are expressed in nonoverlapping patterns in both embryos and imaginal discs, suggesting that transcription of these ncRNAs is associated with repression, not activation, of Ubx. Our data rule out siRNA or miRNA-based mechanisms for repression by bxd ncRNAs. Rather, ncRNA transcription itself, acting in cis, represses Ubx. The Trithorax complex TAC1 binds the Ubx coding region in nuclei expressing Ubx, and the bxd region in nuclei not expressing Ubx. We propose that TAC1 promotes the mosaic pattern of Ubx expression by facilitating transcriptional elongation of bxd ncRNAs, which represses Ubx transcription.