Propagation of silencing:: Recruitment and repression of naive chromatin -: In trans by polycomb repressed chromatin
Propagation of silencing:: Recruitment and repression of naive chromatin -: In trans by polycomb repressed chromatin
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DOI：
10.1016/s1097-2765(04)00006-1
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发表时间：
2004-02-13
期刊：
影响因子：
16
通讯作者：
Kingston, RE
中科院分区：
文献类型：
--
作者：
Lavigne, M;Francis, NJ;Kingston, RE
Polycomb组（PcG）蛋白维持同源异型基因的稳定和可遗传的阻遏。通常，指导PcG阻遏的Polycomb应答元件（PRE）位于距PcG阻遏基因的启动子很远的距离（10kb）处，并且不知道这些PRE如何在这样的距离上与启动子通信。使用II类小鼠PRC核心复合物（mPCCs）组装的重组亚基，我们研究了如何PcG复合物可能会桥遥远的染色体区域。与天然和重组果蝇II类复合物一样，mPCC抑制染色质重塑和转录。有趣的是，与一个多核小体模板结合的mPCC可以从溶液中募集第二个模板，并使其难以转录和染色质重塑。果蝇PRC核心复合物（dPCC）也能够募集第二模板。后性梳（PSC），dPCC的亚基，有效地抑制染色质重塑和转录，但需要与dRING 1组装招募染色质。因此，镇压和模板桥接需要不同的亚基的PcG复合物，这表明，长期的影响可能是机械上不同的镇压。
The Polycomb group (PcG) proteins maintain stable and heritable repression of homeotic genes. Typically, Polycomb response elements (PRE) that direct PcG repression are located at great distances (10s of kb) from the promoters of PcG-repressed genes, and it is not known how these PREs can communicate with promoters over such distances. Using Class II mouse PRC core complexes (mPCCs) assembled from recombinant subunits, we investigated how PcG complexes might bridge distant chromosomal regions. Like native and recombinant Drosophila Class II complexes, mPCC represses chromatin remodeling and transcription. Interestingly, mPCC bound to one polynucleosome template can recruit a second template from solution and renders it refractory to transcription and chromatin remodeling. A Drosophila PRC core complex (dPCC) also is able to recruit a second template. Posterior sex combs (PSC), a subunit of dPCC, inhibits chromatin remodeling and transcription efficiently but requires assembly with dRING1 to recruit chromatin. Thus, repression and template bridging require different subunits of PcG complexes, suggesting that long-range effects may be mechanistically distinct from repression.