Comparing active and repressed expression states of genes controlled by the Polycomb/Trithorax group proteins
Comparing active and repressed expression states of genes controlled by the Polycomb/Trithorax group proteins
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DOI：
10.1073/pnas.0701538104
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发表时间：
2007-10-16
影响因子：
11.1
通讯作者：
Paro, Renato
中科院分区：
文献类型：
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作者：
Beisel, Christian;Buness, Andreas;Paro, Renato
果蝇多梳群(PcG)和三胸群(TrxG)蛋白负责维持许多发育调节基因的稳定转录模式，如同源异型基因。我们使用芯片上的方法比较了几个PcG/TrxG蛋白以及组蛋白修饰在两个同源异型复合体ANT-C和BX-C中激活和抑制基因中的分布。我们的数据表明，多梳抑制复合体1(PRc1)与Trx和DNA结合蛋白PleioHome(Pho)在离散的序列元件上共存，并且在活性区域和非活性区域存在显着的染色质组装差异。Trx与活性基因和非编码转录本的启动子结合。最引人注目的是，在活性状态下，Pho覆盖了数千个碱基上的染色质结构域。在许多多丝染色体泡状物上观察到的Pho的这一特征，反映了以前未描述的功能。在HSP70基因上，我们在突变体中证明了Pho是热休克后转录恢复所必需的。除了它在招募PcG复合体到作用部位的假定功能外，我们的结果现在还发现，Pho在抑制已经诱导的基因方面发挥了额外的作用。
Drosophila Polycomb group (PcG) and Trithorax group (TrxG) proteins are responsible for the maintenance of stable transcription patterns of many developmental regulators, such as the homeotic genes. We have used ChIP-on-chip to compare the distribution of several PcG/TrxG proteins, as well as histone modifications in active and repressed genes across the two homeotic complexes ANT-C and BX-C. Our data indicate the colocalization of the Polycomb repressive complex 1 (PRC1) with Trx and the DNA binding protein Pleiohomeotic (Pho) at discrete sequence elements as well as significant chromatin assembly differences in active and inactive regions. Trx binds to the promoters of active genes and noncoding transcripts. Most strikingly, in the active state, Pho covers extended chromatin domains over many kilobases. This feature of Pho, observed on many polytene chromosome puffs, reflects a previously unclescribed function. At the hsp70 gene, we demonstrate in mutants that Pho is required for transcriptional recovery after heat shock. Besides its presumptive function in recruiting PcG complexes to their site of action, our results now uncover that Pho plays an additional role in the repression of already induced genes.