SETDB1 (SET domain bifurcated histone lysine methyltransferase 1) is a major protein lysine methyltransferase trimethylating lysine 9 on histone H3 (H3K9) which is involved in heterochromatin formation and silencing of repeat elements (REs). It contains a unique Triple Tudor Domain (3TD), which specifically binds the dual modification of H3K14ac in the presence of H3K9me1/2/3. Here, we explored the role of the 3TD H3–tail interaction for the H3K9 methylation activity of SETDB1. We generated a binding reduced 3TD mutant and demonstrate in biochemical methylation assays on peptides and recombinant nucleosomes containing H3K14ac and H3K14ac analogs, respectively, that H3K14 acetylation is crucial for the 3TD mediated recruitment of SETDB1. We also observe this effect in cells where SETDB1 binding and activity is globally correlated with H3K14ac, and knockout of the H3K14 acetyltransferase HBO1 causes a drastic reduction in H3K9me3 levels at SETDB1 dependent sites. Regions with DNA hypomethylation after SETDB1 knockout also show an enrichment in SETDB1-dependent H3K9me3 and H3K14ac. Further analyses revealed that 3TD is particularly important at specific target regions like L1M REs, where H3K9me3 cannot be efficiently reconstituted by the 3TD mutant of SETDB1. In summary, our data demonstrate that the H3K9me3 and H3K14ac are not antagonistic marks but rather the presence of H3K14ac is required for SETDB1 recruitment via 3TD binding to H3K9me1/2/3-K14ac regions and establishment of H3K9me3.

中文翻译：

---

SETDB1 活性由 H3K14 乙酰化通过其三重 Tudor 结构域进行全局指导


SETDB1 （SET domain bifurcated 组蛋白赖氨酸甲基转移酶 1） 是组蛋白 H3 （H3K9） 上的主要赖氨酸甲基转移酶三甲基化赖氨酸 9，参与异染色质形成和重复元件 （RE） 沉默。它包含一个独特的三重 Tudor 结构域 （3TD），在 H3K9me1/2/3 存在下特异性结合 H3K14ac 的双重修饰。在这里，我们探讨了 3TD H3-尾相互作用对 SETDB1 的 H3K9 甲基化活性的作用。我们产生了一个结合还原的 3TD 突变体，并分别在含有 H3K14ac 和 H3K14ac 类似物的肽和重组核小体的生化甲基化测定中证明，H3K14 乙酰化对于 3TD 介导的 SETDB1 募集至关重要。我们还在 SETDB1 结合和活性与 H3K14ac 全局相关的细胞中观察到这种效应，并且敲除 H3K14 乙酰转移酶 HBO1 导致 SETDB1 依赖位点的 H3K9me3 水平急剧降低。SETDB1 敲除后 DNA 低甲基化的区域也显示 SETDB1 依赖性 H3K9me3 和 H3K14ac 富集。进一步分析表明，3TD 在特定靶区域（如 L1M REs）尤为重要，其中 H3K9me3 不能被 SETDB1 的 3TD 突变体有效重构。总之，我们的数据表明 H3K9me3 和 H3K14ac 不是拮抗标志，而是 H3K14ac 的存在是通过 3TD 结合 H3K9me1/2/3-K14ac 区域和 H3K9me3 建立来募集 SETDB1 所必需的。