PRC2 direct transfer from G-quadruplex RNA to dsDNA has implications for RNA-binding chromatin modifiers.
PRC2 direct transfer from G-quadruplex RNA to dsDNA has implications for RNA-binding chromatin modifiers.
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DOI：
10.1073/pnas.2220528120
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发表时间：
2023-06-06
影响因子：
11.1
通讯作者：
Cech, Thomas R.
中科院分区：
文献类型：
--
作者：
Hemphill, Wayne O.;Fenske, Regan;Gooding, Anne R.;Cech, Thomas R.
体外对PRC2的研究表明，RNA通过与核小体的相互拮抗结合抑制其组蛋白甲基转移酶（HMTase）活性，但一些体内研究矛盾地表明，RNA结合是促进其染色质占用和HMTase活性的必要条件。我们的发现揭示了RNA和DNA/核小体在PRC2蛋白复合物上直接交换的机制，通过允许RNA调节PRC2取决于RNA -核小体的接近程度来拮抗或协同，这与之前的发现相一致。此外，人们越来越意识到多种染色质相关蛋白表现出调节RNA结合活性，我们的研究结果表明，这种“直接转移”机制可能通常需要蛋白质向染色质募集RNA。染色质修饰酶多梳抑制复合体2 （Polycomb repression Complex 2, PRC2）沉积H3K27me3表观遗传标记，负调控许多靶基因的表达，这种活性与胚胎发育、细胞分化和各种癌症有关。RNA结合在调节PRC2组蛋白甲基转移酶活性中的生物学作用被普遍接受，但这种关系的性质和机制仍然是一个积极研究的领域。值得注意的是，许多体外研究表明，RNA通过相互拮抗结合抑制核小体上PRC2的活性，而一些体内研究表明，PRC2的RNA结合活性对促进其生物学功能至关重要。在这里，我们使用生化、生物物理和计算方法来询问PRC2的RNA和dna结合动力学。我们的研究结果表明，prc2 -多核苷酸解离率取决于游离配体的浓度，这表明在没有游离酶中间体的情况下，核酸配体之间可能直接转移。直接转移解释了先前报道的解离动力学的变化，允许对先前的体外和体内研究进行协调，并扩展了rna介导的PRC2调控的潜在机制。此外，模拟表明，这种直接转移机制可能是RNA将蛋白质招募到染色质上的必要条件。
Studies of PRC2 in vitro indicate that RNA inhibits its histone methyltransferase (HMTase) activity through mutually antagonistic binding with nucleosomes, but some in vivo studies paradoxically suggest that RNA binding is necessary to facilitate its chromatin occupancy and HMTase activity. Our findings unveil a mechanism for direct exchange of RNA and DNA/nucleosome on the PRC2 protein complex, which reconciles these prior findings by allowing RNA regulation of PRC2 to be antagonistic or synergistic depending on RNA–nucleosome proximity. Furthermore, there is an increasing awareness that multiple chromatin-associated proteins exhibit regulatory RNA binding activity, and our findings indicate that this “direct transfer” mechanism may be generally required for RNA recruitment of proteins to chromatin. The chromatin-modifying enzyme, Polycomb Repressive Complex 2 (PRC2), deposits the H3K27me3 epigenetic mark to negatively regulate expression at numerous target genes, and this activity has been implicated in embryonic development, cell differentiation, and various cancers. A biological role for RNA binding in regulating PRC2 histone methyltransferase activity is generally accepted, but the nature and mechanism of this relationship remains an area of active investigation. Notably, many in vitro studies demonstrate that RNA inhibits PRC2 activity on nucleosomes through mutually antagonistic binding, while some in vivo studies indicate that PRC2’s RNA-binding activity is critical for facilitating its biological function(s). Here we use biochemical, biophysical, and computational approaches to interrogate PRC2’s RNA and DNA-binding kinetics. Our findings demonstrate that PRC2-polynucleotide dissociation rates are dependent on the concentration of free ligand, indicating the potential for direct transfer between nucleic acid ligands without a free-enzyme intermediate. Direct transfer explains the variation in previously reported dissociation kinetics, allows reconciliation of prior in vitro and in vivo studies, and expands the potential mechanisms of RNA-mediated PRC2 regulation. Moreover, simulations indicate that such a direct transfer mechanism could be obligatory for RNA to recruit proteins to chromatin.
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影响因子：
16
作者：
Cifuentes-Rojas, Catherine;Hernandez, Alfredo J.;Sarma, Kavitha;Lee, Jeannie T.
通讯作者：
Lee, Jeannie T.
影响因子：
7.2
作者：
Gillooly, James F.;Hein, Andrew;Damiani, Rachel
通讯作者：
Damiani, Rachel
影响因子：
5.6
作者：
BRESLOFF, JL;CROTHERS, DM
通讯作者：
CROTHERS, DM
DOI：
10.1073/pnas.0805050105
发表时间：
2008-09-16
影响因子：
11.1
作者：
Doucleff, Michaeleen;Clore, G. Marius
通讯作者：
Clore, G. Marius
影响因子：
64.5
作者：
Czermin, B;Melfi, R;Pirrotta, V
通讯作者：
Pirrotta, V