Protein arginine methylation, an evolutionarily conserved post-translational modification, serves critical cellular functions by transferring a methyl group to a variety of substrates, including histones and some transcription factors. In budding yeast, Hsl7 (histone synthetic lethal 7) displays type II PRMT (protein arginine methyltransferase) activity by generating symmetric dimethylarginine residues on histone H2A in vitro. However, identification of the in vivo substrate of Hsl7 and how it contributes to important cellular processes remain largely unexplored. In the present study, we show that Hsl7 has a repressive role in transcription. We found that Hsl7 is responsible for in vivo symmetric dimethylation of histone H4 arginine 3 (H4R3me2s) in a transcriptionally repressed state. Tandem affinity purification further demonstrated that Hsl7 physically interacts with histone deacetylase Rpd3, and both similarly repress transcription. Our results suggest that H4R3me2s generation by the type II PRMT Hsl7 is required for transcriptional repression, possibly in cooperation with histone deacetylation by Rpd3.

中文翻译：

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酵母对称的精氨酸甲基转移酶Hs17在转录中具有抑制作用。

蛋白质精氨酸甲基化是一种进化上保守的翻译后修饰，它通过将甲基转移至包括组蛋白和某些转录因子在内的多种底物来发挥关键的细胞功能。在发芽的酵母中，Hs17（组蛋白合成致死7）通过在体外组蛋白H2A上产生对称的二甲基精氨酸残基，显示II型PRMT（蛋白质精氨酸甲基转移酶）活性。然而，关于Hs17的体内底物的鉴定以及它如何对重要的细胞过程作出贡献，在很大程度上尚待探索。在本研究中，我们显示Hsl7在转录中具有抑制作用。我们发现，Hsl7负责在转录抑制状态下组蛋白H4精氨酸3（H4R3me2s）的体内对称二甲基化。串联亲和纯化进一步证明，Hs17与组蛋白脱乙酰基酶Rpd3发生物理相互作用，并且两者均相似地抑制转录。我们的结果表明，II型PRMT Hsl7产生H4R3me2s是转录抑制所必需的，可能与Rpd3的组蛋白脱乙酰作用配合使用。