The PHD finger protein Spp1 has distinct functions in the Set1 and the meiotic DSB formation complexes.
The PHD finger protein Spp1 has distinct functions in the Set1 and the meiotic DSB formation complexes.
复制标题
DOI：
10.1371/journal.pgen.1007223
复制
发表时间：
2018-03
期刊：
影响因子：
4.5
通讯作者：
Borde V
中科院分区：
文献类型：
--
作者：
Adam C;Guérois R;Citarella A;Verardi L;Adolphe F;Béneut C;Sommermeyer V;Ramus C;Govin J;Couté Y;Borde V
组蛋白 H3K4 甲基化是包括植物和哺乳动物在内的许多生物体共有的减数分裂重组热点的一个特征。减数分裂重组是由程序性双链断裂 (DSB) 形成启动的，在芽殖酵母中，双链断裂 (DSB) 发生在基因启动子中，并由组蛋白 H3K4 二甲基化/三甲基化促进。这种组蛋白修饰可被 Spp1 识别，Spp1 是一种 PHD 指，含有属于保守组蛋白 H3K4 甲基转移酶 Set1 复合体的蛋白质。在减数分裂过程中，Spp1 结合 H3K4me3 并与 DSB 蛋白 Mer2 相互作用，促进靠近基因启动子的 DSB 形成。 Spp1 的 Set1 复合体和 Mer2 相关功能如何连接尚不清楚。在这里，结合全基因组定位分析、生化方法和功能突变体分离的使用，我们表明 Spp1 存在于减数分裂细胞中两个不同的复合体中，即 Set1 和 Mer2 复合体。破坏 Spp1-Set1 相互作用会轻微降低 H3K4me3 水平，并且不会影响减数分裂重组的启动。相反，Spp1-Mer2 相互作用是正常减数分裂重组启动所必需的，但对于 Set1 复合物介导的组蛋白 H3K4 甲基化来说是可有可无的。最后，我们提供证据表明 Spp1 独立于 Set1 复合物保留正常的 H3K4me3 水平。我们提出了一个模型，其中 Spp1 以三种方式发挥作用来促进重组起始：首先通过沉积组蛋白 H3K4 甲基化（Set1 复合物），接下来通过“读取”和保护组蛋白 H3K4 甲基化，最后通过与染色体轴（Mer2-Spp1 复合物）建立连接。这项工作破译了 Spp1 在减数分裂重组中的精确作用，并为研究其在重组热点中也存在 H3K4me3 的其他生物体中的功能开辟了视角。减数分裂重组是有性生殖的保守途径，需要忠实地分离同源染色体并产生可行的配子。同源染色体之间的重组事件是由 DNA 断裂的程序化形成触发的，这种断裂优先发生在称为热点的地方。在许多生物体中，这些热点靠近特定的染色质修饰，即组蛋白 H3 赖氨酸 4 (H3K4me3) 的甲基化。之前在芽殖酵母模型中表明，一种蛋白质 Spp1 在此过程中发挥着重要作用。我们进一步探索了 Spp1 及其相互作用伙伴之间的功能联系，并表明 Spp1 通过在染色质上沉积 H3K4me3 标记、“读取”并保护它，并将其与重组蛋白连接，显示出遗传上可分离的功能。我们提供的证据表明 Spp1 处于不同的复合体中来执行这些功能。这项工作为理解其他真核生物（例如哺乳动物）的过程开辟了新的视角，其中涉及的大多数蛋白质都是保守的。
Histone H3K4 methylation is a feature of meiotic recombination hotspots shared by many organisms including plants and mammals. Meiotic recombination is initiated by programmed double-strand break (DSB) formation that in budding yeast takes place in gene promoters and is promoted by histone H3K4 di/trimethylation. This histone modification is recognized by Spp1, a PHD finger containing protein that belongs to the conserved histone H3K4 methyltransferase Set1 complex. During meiosis, Spp1 binds H3K4me3 and interacts with a DSB protein, Mer2, to promote DSB formation close to gene promoters. How Set1 complex- and Mer2- related functions of Spp1 are connected is not clear. Here, combining genome-wide localization analyses, biochemical approaches and the use of separation of function mutants, we show that Spp1 is present within two distinct complexes in meiotic cells, the Set1 and the Mer2 complexes. Disrupting the Spp1-Set1 interaction mildly decreases H3K4me3 levels and does not affect meiotic recombination initiation. Conversely, the Spp1-Mer2 interaction is required for normal meiotic recombination initiation, but dispensable for Set1 complex-mediated histone H3K4 methylation. Finally, we provide evidence that Spp1 preserves normal H3K4me3 levels independently of the Set1 complex. We propose a model where Spp1 works in three ways to promote recombination initiation: first by depositing histone H3K4 methylation (Set1 complex), next by “reading” and protecting histone H3K4 methylation, and finally by making the link with the chromosome axis (Mer2-Spp1 complex). This work deciphers the precise roles of Spp1 in meiotic recombination and opens perspectives to study its functions in other organisms where H3K4me3 is also present at recombination hotspots. Meiotic recombination is a conserved pathway of sexual reproduction that is required to faithfully segregate homologous chromosomes and produce viable gametes. Recombination events between homologous chromosomes are triggered by the programmed formation of DNA breaks, which occur preferentially at places called hotspots. In many organisms, these hotspots are located close to a particular chromatin modification, the methylation of lysine 4 of histone H3 (H3K4me3). It was previously shown in the budding yeast model that one protein, Spp1, plays an important function in this process. We further explored the functional link between Spp1 and its interacting partners, and show that Spp1 shows genetically separable functions, by depositing the H3K4me3 mark on the chromatin, “reading” and protecting it, and linking it to the recombination proteins. We provide evidence that Spp1 is in distinct complexes to perform these functions. This work opens perspectives for understanding the process in other eukaryotes such as mammals, where most of the proteins involved are conserved.
登录
查看更多内容
影响因子：
30.8
作者：
Choi, Kyuha;Zhao, Xiaohui;Kelly, Krystyna A.;Venn, Oliver;Higgins, James D.;Yelina, Nataliya E.;Hardcastle, Thomas J.;Ziolkowski, Piotr A.;Copenhaver, Gregory P.;Franklin, F. Chris H.;McVean, Gil;Henderson, Ian R.
通讯作者：
Henderson, Ian R.
映射减数分裂的单链DNA揭示了酿酒酵母中DNA双链断裂的新景观。
影响因子：
9.8
作者：
Buhler, Cyril;Borde, Valerie;Lichten, Michael
通讯作者：
Lichten, Michael
影响因子：
1.6
作者：
Imai Y;Baudat F;Taillepierre M;Stanzione M;Toth A;de Massy B
通讯作者：
de Massy B
影响因子：
4.5
作者：
Auton A;Rui Li Y;Kidd J;Oliveira K;Nadel J;Holloway JK;Hayward JJ;Cohen PE;Greally JM;Wang J;Bustamante CD;Boyko AR
通讯作者：
Boyko AR
影响因子：
10.5
作者：
Cole, Francesca;Keeney, Scott;Jasin, Maria
通讯作者：
Jasin, Maria