Heterochromatin protein 1 (HP1) connects the FACT histone chaperone complex to the phosphorylated CTD of RNA polymerase II
Heterochromatin protein 1 (HP1) connects the FACT histone chaperone complex to the phosphorylated CTD of RNA polymerase II
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DOI：
10.1101/gad.1959110
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发表时间：
2010-10-01
影响因子：
10.5
通讯作者：
Workman, Jerry L.
中科院分区：
文献类型：
--
作者：
Kwon, So Hee;Florens, Laurence;Workman, Jerry L.
异染色质蛋白1（Heterochromatin protein 1，HP1）是一种位于臂间异染色质的沉默蛋白。大多数真核生物具有至少三种在异染色质和常染色质中发挥不同作用的HP1同种型。除了其在异染色质中的作用之外，HP1蛋白已被证明在转录延伸中起作用。为了深入了解HP1的转录功能，我们试图鉴定新的HP1相互作用蛋白。生物化学和蛋白质组学方法揭示，HP1与组蛋白伴侣复合物FACT（促进染色质转录）相互作用。HP1c与SSRP 1（结构特异性识别蛋白1）亚基和完整的FACT复合物相互作用。此外，HP1c引导FACT向活性基因的募集，并将FACT与RNA聚合酶II的活性形式联系起来。HP1c的缺失部分削弱了FACT进入热休克基因座的募集，并导致热休克基因表达缺陷。因此，HP1c的功能是将FACT复合物募集到RNA聚合酶II。
Heterochromatin protein 1 (HP1) is well known as a silencing protein found at pericentric heterochromatin. Most eukaryotes have at least three isoforms of HP1 that play differential roles in heterochromatin and euchromatin. In addition to its role in heterochromatin, HP1 proteins have been shown to function in transcription elongation. To gain insights into the transcription functions of HP1, we sought to identify novel HP1-interacting proteins. Biochemical and proteomic approaches revealed that HP1 interacts with the histone chaperone complex FACT (facilitates chromatin transcription). HP1c interacts with the SSRP1 (structure-specific recognition protein 1) subunit and the intact FACT complex. Moreover, HP1c guides the recruitment of FACT to active genes and links FACT to active forms of RNA polymerase II. The absence of HP1c partially impairs the recruitment of FACT into heat-shock loci and causes a defect in heat-shock gene expression. Thus, HP1c functions to recruit the FACT complex to RNA polymerase II.