Pumilio paralogs, PUM1 and PUM2, are sequence-specific RNA-binding proteins that are essential for vertebrate development and neurological functions. PUM1&2 negatively regulate gene expression by accelerating degradation of specific mRNAs. Here, we determined the repression mechanism and impact of human PUM1&2 on the transcriptome. We identified subunits of the CCR4-NOT (CNOT) deadenylase complex required for stable interaction with PUM1&2 and to elicit CNOT-dependent repression. Isoform-level RNA sequencing revealed broad co-regulation of target mRNAs through the PUM-CNOT repression mechanism. Functional dissection of the domains of PUM1&2 identified a conserved N-terminal region that confers the predominant repressive activity via direct interaction with CNOT. In addition, we show that the mRNA decapping enzyme, DCP2, has an important role in repression by PUM1&2 N-terminal regions. Our results support a molecular model of repression by human PUM1&2 via direct recruitment of CNOT deadenylation machinery in a decapping-dependent mRNA decay pathway.

中文翻译：

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人 Pumilio 蛋白直接结合 CCR4-NOT 去腺苷酶复合物以调节转录组

Pumilio paralogs，PUM1 和 PUM2，是序列特异性 RNA 结合蛋白，对脊椎动物发育和神经功能至关重要。PUM1&2 通过加速特定 mRNA 的降解负调控基因表达。在这里，我们确定了人类 PUM1&2 对转录组的抑制机制和影响。我们确定了与 PUM1&2 稳定相互作用并引发 CNOT 依赖性抑制所需的 CCR4-NOT (CNOT) 去腺苷酶复合物的亚基。异构体水平的 RNA 测序揭示了靶 mRNA 通过 PUM-CNOT 抑制机制的广泛共调节。PUM1&2 结构域的功能剖析确定了一个保守的 N 末端区域，该区域通过与 CNOT 的直接相互作用赋予主要的抑制活性。此外，我们发现 mRNA 脱壳酶 DCP2 在 PUM1 和 2 N 末端区域的抑制中起重要作用。我们的结果支持人类 PUM1 和 2 通过在脱帽依赖性 mRNA 衰变途径中直接募集 CNOT 去腺苷酸化机制来抑制的分子模型。