Binding of Trithorax and Polycomb proteins to the bithorax complex:: dynamic changes during early Drosophila embryogenesis
Binding of Trithorax and Polycomb proteins to the bithorax complex:: dynamic changes during early Drosophila embryogenesis
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DOI：
10.1093/emboj/17.17.5141
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发表时间：
1998-09-01
期刊：
影响因子：
11.4
通讯作者：
Paro, R
中科院分区：
文献类型：
--
作者：
Orlando, V;Jane, EP;Paro, R
在果蝇中，对发育至关重要的转录模式的维持在染色质结构水平上受到控制。Polycomb group （PcG）和trithorax group （trxG）基因编码参与染色质重塑的蛋白质，PcG基因被认为通过将转录抑制的染色体结构域包装成凝聚的异染色质样结构来起作用。目前已知的一些trxG蛋白是染色质开放复合物（如SWI/SNF和GAGA/NURF）的成员，它们促进转录因子和基础转录机制成分的结合。遗传和生化数据表明，这两组调节因子可能通过一组共同的DNA元件起作用。在本研究中，我们研究了胚胎发生过程中Trithorax （TRX）和Polycomb （PC）蛋白在bithorax复合物（BX-C）中的结合。此外，我们已经从UItrabithorax （Ubx）调控区域中鉴定出能够将TRX招募到含有它们的染色体位点的最小片段。两种蛋白结合的对比分析表明，当BX-C开始转录时，TRX和PC通过细胞囊胚结合靶序列（pcg调控元件，PREs）。在同一阶段，TRX而非PC与核心启动子密切相关。随后，在Polycomb突变体的胚芽带延伸，即抑制时间，PC结合也在核心PREs外被检测到，并且另外结合到含有启动子的片段上。
In Drosophila, the maintenance of developmentally important transcription patterns is controlled at the level of chromatin structure. The Polycomb group (PcG) and trithorax group (trxG) genes encode proteins involved in chromatin remodelling, PcG genes have been proposed to act by packaging transcriptional repressed chromosomal domains into condensed heterochromatin-like structures. Some of the trxG proteins characterized so far are members of chromatin opening complexes (e.g. SWI/SNF and GAGA/NURF) which facilitate binding of transcription factors and components of the basal transcriptional machinery. Genetic and biochemical data suggest that these two groups of regulatory factors may act through a common set of DNA elements. In the present study, we have investigated the binding of Trithorax (TRX) and Polycomb (PC) protein in the bithorax complex (BX-C) during embryogenesis. In addition, we have identified the minimal fragments from the UItrabithorax (Ubx) regulatory region that are capable of recruiting TRX to chromosomal sites containing them. Comparative analysis of the binding of the two proteins shows that TRX and PC bind target sequences (PcG-regulated elements, PREs) by cellular blastoderm, when BX-C transcription begins. At the same stage, TRX but not PC is strongly associated with core promoters. Later, at germ band extension, the time of derepression in Polycomb mutants, PC binding is also detected outside core PREs and additionally binds to the fragments containing promoters.