JARID2 and AEBP2 regulate PRC2 in the presence of H2AK119ub1 and other histone modifications.
JARID2 and AEBP2 regulate PRC2 in the presence of H2AK119ub1 and other histone modifications.
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DOI：
10.1126/science.abc3393
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发表时间：
2021-01-22
期刊：
影响因子：
--
通讯作者：
Nogales E
中科院分区：
文献类型：
--
作者：
Kasinath V;Beck C;Sauer P;Poepsel S;Kosmatka J;Faini M;Toso D;Aebersold R;Nogales E
多梳阻遏复合物1和2（PRC 1和PRC 2）的组蛋白修饰活性对于基因表达模式的建立和维持以及因此对于细胞身份的维持是至关重要的。已知不同类别的辅因子蛋白调节这两种复合物的功能活性和相互作用，但我们目前缺乏对这一过程的全面、机制性理解。此外，PRC 2辅因子如AEBP 2和JARID 2也在介导不同组蛋白翻译后修饰与PRC 2募集和活性之间的串扰中发挥作用，这一功能对于基因表达的调控是重要的。PRC 1是一种E3泛素连接酶，负责组蛋白H2 A（H2 AK 119 ub 1）的单泛素化，H2 A是一种由PRC 2识别并与其基因组募集相关的组蛋白标记。我们使用冷冻电子显微镜（cryo-EM）和生化活性测定来探测PRC 2辅因子JARID 2和AEBP 2在识别H2 AK 119 ub 1和调节PRC 2活性中所起的作用。我们扩展了我们的cryo-EM和生化活性分析，以检查JARID 2和AEBP 2在与转录活性区域相关的组蛋白H3 K4 me 3、H3 K36 me 3修饰和PRC 2活性之间的串扰中可能发挥的作用。我们发现JARID 2既识别H2 AK 119 ub 1中的泛素部分，也识别保守的组蛋白H2 A-H2 B酸性斑块。我们还观察到AEBP 2的串联锌指与核小体另一侧的泛素和组蛋白H2 A-H2 B表面相互作用。生化分析显示，除了甲基化JARID 2对PRC 2的主要EED介导的变构激活外，JARID 2和AEBP 2对含H2 AK 119 ub 1的核小体的PRC 2的二次激活。此外，我们还发现JARID 2和AEBP 2的共同存在部分降低了转录活性组蛋白翻译后修饰H3 K4 me 3和H3 K36 me 3对PRC 2甲基转移酶活性的抑制。包含JARID 2和AEBP 2的PRC 2与含H3 K4 me 3的核小体相互作用的Cryo-EM可视化显示了组蛋白H3尾部不存在或接合并到达PRC 2中的催化位点的状态的共存，这为复合物对含H3 K4 me 3的核小体的部分活性提供了物理基础。我们的研究表明，辅助因子JARID 2和AEBP 2通过识别由PRC 1产生的H2 AK 119 ub 1，在PRC 2的募集和激活中起着至关重要的作用。此外，我们的工作表明，JARID 2和AEBP 2可能在调节PRC 2活性的基因组区域与活跃的转录标记发挥关键作用。PRC 2核心蛋白与JARID 2和AEBP 2一起在胚胎干细胞中的基因组分布的检查对于进一步确定它们在PRC 2活性的严格调节中的作用将是重要的。多梳抑制复合物1和2（PRC 1和PRC 2）通过表观遗传基因表达调控协同确定细胞身份。然而，PRC 2通过识别PRC 1介导的H2 AK 119 ub 1的募集机制仍然知之甚少。我们的PRC 2冷冻电子显微镜结构与辅因子JARID 2和AEBP 2结合到一个H2 AK 119 ub 1-含有核小体揭示了一个桥螺旋EZH 2连接SET域，H3尾，和核小体DNA。JARID 2和AEBP 2各自与一个泛素和H2 A-H2 B表面相互作用。JARID 2通过与多梳蛋白EED和H2 AK 119-泛素的相互作用刺激PRC 2，而AEBP 2具有额外的支架作用。这些辅因子的存在部分地克服了H3 K4 me 3和H3 K36 me 3对核心PRC 2施加的抑制作用（在不存在辅因子的情况下）。我们的研究结果支持JARID 2和AEBP 2在组蛋白修饰和PRC 2活性之间的交叉作用中的关键作用。虽然核心PRC 2是一种弱酶，但它被JARID 2和AEBP 2变构激活。PRC 1活性的产物单泛素化组蛋白H2 A的存在被JARID 2和AEBP 2通过相互作用识别，所述相互作用可能介导PRC 2募集到基因组中的多梳位点，并进一步激活PRC 2对组蛋白H3的K27的甲基转移酶活性。
Histone modification activity of the polycomb repressive complexes 1 and 2 (PRC1 and PRC2) is critical for the establishment and maintenance of gene expression patterns and, thus, to the maintenance of cell identity. Distinct classes of cofactor proteins are known to regulate the functional activity and interplay of these two complexes, but we presently lack a comprehensive, mechanistic understanding of this process. Furthermore, PRC2 cofactors like AEBP2 and JARID2 also play a role in mediating the cross-talk between different histone posttranslational modifications and PRC2 recruitment and activity—a function that is important for the regulated control of gene expression. PRC1 is an E3 ubiquitin ligase responsible for the monoubiquitination of histone H2A (H2AK119ub1), a histone mark recognized by PRC2 and linked to its genomic recruitment. We used cryo-electron microscopy (cryo-EM) and biochemical activity assays to probe the role played by PRC2 cofactors JARID2 and AEBP2 in the recognition of H2AK119ub1 and the regulation of PRC2 activity. We extended our cryo-EM and biochemical activity analysis to examine the possible role played by JARID2 and AEBP2 in the cross-talk between the histone H3K4me3, H3K36me3 modifications linked to transcriptionally active regions, and PRC2 activity. We find that JARID2 recognizes both the ubiquitin moiety in H2AK119ub1 and the conserved histone H2A-H2B acidic patch. We also observe that the tandem zinc fingers of AEBP2 interact with ubiquitin and the histone H2A-H2B surface on the other side of the nucleosome. Biochemical assays show a secondary activation of PRC2 by JARID2 and AEBP2 on H2AK119ub1-containing nucleosomes besides the primary EED-mediated allosteric activation of PRC2 by methylated JARID2. Furthermore, we also find that the joint presence of JARID2 and AEBP2 partially reduces the inhibition of PRC2 methyltransferase activity by the transcriptionally active histone posttranslational modifications H3K4me3 and H3K36me3. Cryo-EM visualization of PRC2 that contains JARID2 and AEBP2 interacting with a H3K4me3-containing nucleosome shows the coexistence of states in which the histone H3 tail is either absent or engaged and reaching the catalytic site in PRC2, which provides a physical basis for the partial activity of the complex on H3K4me3-containing nucleosomes. Our studies indicate that cofactors JARID2 and AEBP2 play a crucial role in both the recruitment and activation of PRC2 through their recognition of H2AK119ub1, which is generated by PRC1. Additionally, our work suggests that JARID2 and AEBP2 are likely to play a key role in regulating PRC2 activity on genomic regions with active transcription marks. The examination of the genomic distribution in embryonic stem cells of PRC2 core proteins together with JARID2 and AEBP2 will be important to further define their role in the tight regulation of PRC2 activity. Polycomb repressive complexes 1 and 2 (PRC1 and PRC2) cooperate to determine cell identity by epigenetic gene expression regulation. However, the mechanism of PRC2 recruitment by means of recognition of PRC1-mediated H2AK119ub1 remains poorly understood. Our PRC2 cryo-electron microscopy structure with cofactors JARID2 and AEBP2 bound to a H2AK119ub1-containing nucleosome reveals a bridge helix in EZH2 that connects the SET domain, H3 tail, and nucleosomal DNA. JARID2 and AEBP2 each interact with one ubiquitin and the H2A-H2B surface. JARID2 stimulates PRC2 through interactions with both the polycomb protein EED and the H2AK119-ubiquitin, whereas AEBP2 has an additional scaffolding role. The presence of these cofactors partially overcomes the inhibitory effect that H3K4me3 and H3K36me3 exert on core PRC2 (in the absence of cofactors). Our results support a key role for JARID2 and AEBP2 in the cross-talk between histone modifications and PRC2 activity. Although core PRC2 is a weak enzyme, it is allosterically activated by JARID2 and AEBP2. The presence of monoubiquitinated histone H2A, the product of PRC1 activity, is recognized by both JARID2 and AEBP2 through interactions that likely mediate recruitment of PRC2 to polycomb sites in the genome and further activate the methyltransferase activity of PRC2 on K27 of histone H3.
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影响因子：
16.6
作者：
Justin N;Zhang Y;Tarricone C;Martin SR;Chen S;Underwood E;De Marco V;Haire LF;Walker PA;Reinberg D;Wilson JR;Gamblin SJ
通讯作者：
Gamblin SJ
影响因子：
16.8
作者：
Kaneko, Syuzo;Son, Jinsook;Shen, Steven S.;Reinberg, Danny;Bonasio, Roberto
通讯作者：
Bonasio, Roberto
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
56.9
作者：
Kasinath, Vignesh;Faini, Marco;Nogales, Eva
通讯作者：
Nogales, Eva
影响因子：
10.5
作者：
Li, Gang;Margueron, Raphael;Reinberg, Danny
通讯作者：
Reinberg, Danny