The chromatin-binding E3 ubiquitin ligase ubiquitin-like with PHD and RING finger domains 1 (UHRF1) contributes to the maintenance of aberrant DNA methylation patterning in cancer cells through multivalent histone and DNA recognition. The tandem Tudor domain (TTD) of UHRF1 is well-characterized as a reader of lysine 9 di- and tri-methylation on histone H3 (H3K9me2/me3) and, more recently, lysine 126 di- and tri-methylation on DNA ligase 1 (LIG1K126me2/me3). However, the functional significance and selectivity of these interactions remain unclear. In this study, we used protein domain microarrays to search for additional readers of LIG1K126me2, the preferred methyl state bound by the UHRF1 TTD. We show that the UHRF1 TTD binds LIG1K126me2 with high affinity and selectivity compared to other known methyllysine readers. Notably, and unlike H3K9me2/me3, the UHRF1 plant homeodomain (PHD) and its N-terminal linker (L2) do not contribute to multivalent LIG1K126me2 recognition along with the TTD. To test the functional significance of this interaction, we designed a LIG1K126me2 cell-penetrating peptide (CPP). Consistent with LIG1 knockdown, uptake of the CPP had no significant effect on the propagation of DNA methylation patterning across the genomes of bulk populations from high-resolution analysis of several cancer cell lines. Further, we did not detect significant changes in DNA methylation patterning from bulk cell populations after chemical or genetic disruption of lysine methyltransferase activity associated with LIG1K126me2 and H3K9me2. Collectively, these studies identify UHRF1 as a selective reader of LIG1K126me2 in vitro and further implicate the histone and non-histone methyllysine reader activity of the UHRF1 TTD as a dispensable domain function for cancer cell DNA methylation maintenance.

中文翻译：

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UHRF1 串联 Tudor 结构域的组蛋白和非组蛋白甲基赖氨酸阅读器活性对于癌细胞中异常 DNA 甲基化模式的传播是不必要的

具有 PHD 和环指结构域 1 (UHRF1) 的染色质结合 E3 泛素连接酶泛素样通过多价组蛋白和 DNA 识别有助于维持癌细胞中异常的 DNA 甲基化模式。UHRF1 的串联 Tudor 结构域 (TTD) 被很好地表征为组蛋白 H3 (H3K9me2/me3) 上赖氨酸 9 二甲基化和三甲基化以及最近 DNA 连接酶 1 上赖氨酸 126 二甲基和三甲基化的读取器(LIG1K126me2/me3)。然而，这些相互作用的功能意义和选择性仍不清楚。在这项研究中，我们使用蛋白质结构域微阵列来搜索 LIG1K126me2 的其他阅读器，这是 UHRF1 TTD 结合的首选甲基状态。我们表明，与其他已知的甲基赖氨酸读取器相比，UHRF1 TTD 以高亲和力和选择性结合 LIG1K126me2。尤其，与 H3K9me2/me3 不同，UHRF1 植物同源域 (PHD) 及其 N 端接头 (L2) 不会与 TTD 一起参与多价 LIG1K126me2 识别。为了测试这种相互作用的功能意义，我们设计了一种 LIG1K126me2 细胞穿透肽 (CPP)。与 LIG1 敲低一致，CPP 的摄取对几种癌细胞系的高分辨率分析对 DNA 甲基化模式在大量群体基因组中的传播没有显着影响。此外，在与 LIG1K126me2 和 H3K9me2 相关的赖氨酸甲基转移酶活性发生化学或遗传破坏后，我们没有检测到大量细胞群中 DNA 甲基化模式的显着变化。集体，