The elongator complex interacts with PCNA and modulates transcriptional silencing and sensitivity to DNA damage agents.
The elongator complex interacts with PCNA and modulates transcriptional silencing and sensitivity to DNA damage agents.
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DOI：
10.1371/journal.pgen.1000684
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发表时间：
2009-10
期刊：
影响因子：
4.5
通讯作者：
Stillman B
中科院分区：
文献类型：
--
作者：
Li Q;Fazly AM;Zhou H;Huang S;Zhang Z;Stillman B
在增殖细胞核抗原（PCNA）依赖过程中，组蛋白伴侣caf1和Asf1的作用是将新合成的组蛋白沉积在复制的DNA上，促进核小体的形成。DNA复制或DNA修复偶联的核小体组装途径对于维持转录基因沉默和基因组稳定性是重要的。然而，这些途径是如何被调控的还不是很清楚。在这里，我们报告了延长组蛋白乙酰转移酶和增殖细胞核抗原之间的相互作用。缺乏6亚基拉长复合体的催化亚基Elp3 （k -乙酰转移酶Kat9）的细胞，在染色体VIIL端粒和HMR位点部分失去了报告基因的沉默，并且对DNA复制抑制剂羟基脲（HU）和破坏剂甲基磺酸盐（MMS）敏感。与ELP3的缺失一样，ELP3的其他四个亚基的突变以及ELP3的突变损害了拉长复合体的形成，也会导致沉默缺失和HU敏感性增加。此外，在HU存在的情况下，s相进展需要Elp3。上位分析表明，elp3Δ突变体本身对MMS敏感，但却加剧了缺乏组蛋白伴侣蛋白Asf1、ca -1和H3赖氨酸56乙酰转移酶Rtt109的细胞对MMS的敏感性。elp3Δ突变体与编码PCNA的POL30突变具有等位基因特异性遗传相互作用，PCNA在体内和体外都与伸长复合物结合。总之，这些结果揭示了完整的伸长复合体在转录沉默和维持基因组稳定性中的新作用，并且它是在与DNA复制和DNA修复蛋白PCNA相关的途径中实现的。在细胞周期的S期，不仅DNA序列必须忠实地复制，染色质结构也必须遗传到子细胞中，以维持基因表达状态和细胞身份。虽然在理解DNA复制的调控方面取得了重大进展，但染色质结构如何从一个细胞分裂周期维持到下一个细胞分裂周期（所谓的表观遗传）只是部分了解。认为DNA复制耦合核小体组装过程在这种遗传和维持基因组稳定性中起着重要作用。在这一过程中，组蛋白伴侣如染色质组装因子1 （caf1）将新合成的组蛋白H3-H4（在特定赖氨酸残基上乙酰化）沉积在PCNA依赖反应中复制DNA上。PCNA是DNA聚合酶和其他参与DNA复制和DNA修复的蛋白质的钳子。描述了赖氨酸乙酰转移酶Elp3与DNA复制偶联核小体组装相关因子之间的遗传相互作用。Elp3是转录沉默和维持基因组稳定性所必需的，并直接与PCNA结合。延长复合体在响应DNA损伤和维持基因沉默中的作用进行了讨论。
Histone chaperones CAF-1 and Asf1 function to deposit newly synthesized histones onto replicating DNA to promote nucleosome formation in a proliferating cell nuclear antigen (PCNA) dependent process. The DNA replication- or DNA repair-coupled nucleosome assembly pathways are important for maintenance of transcriptional gene silencing and genome stability. However, how these pathways are regulated is not well understood. Here we report an interaction between the Elongator histone acetyltransferase and the proliferating cell nuclear antigen. Cells lacking Elp3 (K-acetyltransferase Kat9), the catalytic subunit of the six-subunit Elongator complex, partially lose silencing of reporter genes at the chromosome VIIL telomere and at the HMR locus, and are sensitive to the DNA replication inhibitor hydroxyurea (HU) and the damaging agent methyl methanesulfonate (MMS). Like deletion of the ELP3, mutation of each of the four other subunits of the Elongator complex as well as mutations in Elp3 that compromise the formation of the Elongator complex also result in loss of silencing and increased HU sensitivity. Moreover, Elp3 is required for S-phase progression in the presence of HU. Epistasis analysis indicates that the elp3Δ mutant, which itself is sensitive to MMS, exacerbates the MMS sensitivity of cells lacking histone chaperones Asf1, CAF-1 and the H3 lysine 56 acetyltransferase Rtt109. The elp3Δ mutant has allele specific genetic interactions with mutations in POL30 that encodes PCNA and PCNA binds to the Elongator complex both in vivo and in vitro. Together, these results uncover a novel role for the intact Elongator complex in transcriptional silencing and maintenance of genome stability, and it does so in a pathway linked to the DNA replication and DNA repair protein PCNA. During S phase of the cell cycle, not only must DNA sequences be faithfully duplicated, chromatin structures must also be inherited into daughter cells to maintain gene expression states and cell identity. While significant progress has been made in understanding the regulation of DNA replication, how chromatin structures are maintained from one cell division cycle to the next (so-called epigenetic inheritance) is only partially understood. It is believed that the DNA replication-coupled nucleosome assembly process plays an important role in such inheritance as well as maintenance of genome stability. In this process, histone chaperones such as chromatin assembly factor 1 (CAF-1) deposit newly synthesized histones H3–H4, which are acetylated at specific lysine residues, onto replicating DNA in a PCNA dependent reaction. PCNA is a clamp for DNA polymerases and other proteins that are involved in DNA replication and DNA repair. Genetic interactions between lysine acetyltransferase Elp3 and factors involved in DNA replication-coupled nucleosome assembly are described. Elp3 is required for transcriptional silencing and for maintenance of genome stability and binds directly to PCNA. A role for the Elongator complex in response to DNA damage and in maintenance of gene silencing is discussed.
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DOI：
10.1126/science.1135862
发表时间：
2007-02-02
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Driscoll R;Hudson A;Jackson SP
通讯作者：
Jackson SP
影响因子：
5.3
作者：
Fillingham, Jeffrey;Recht, Judith;Greenblatt, Jack F.
通讯作者：
Greenblatt, Jack F.
影响因子：
56.9
作者：
Han, Junhong;Zhou, Hui;Zhang, Zhiguo
通讯作者：
Zhang, Zhiguo
影响因子：
5.3
作者：
Alvino, Gina M.;Collingwood, David;Raghuraman, M. K.
通讯作者：
Raghuraman, M. K.
影响因子：
64.8
作者：
Collins, Sean R.;Miller, Kyle M.;Krogan, Nevan J.
通讯作者：
Krogan, Nevan J.