Trim25 Is an RNA-Specific Activator of Lin28a/TuT4-Mediated Uridylation.
Trim25 Is an RNA-Specific Activator of Lin28a/TuT4-Mediated Uridylation.
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DOI：
10.1016/j.celrep.2014.10.017
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发表时间：
2014-11-20
期刊：
影响因子：
8.8
通讯作者：
Michlewski G
中科院分区：
文献类型：
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作者：
Choudhury NR;Nowak JS;Zuo J;Rappsilber J;Spoel SH;Michlewski G
RNA结合蛋白具有数千个细胞RNA靶点，并且通常表现出相反或被动的分子功能。Lin 28 a是一种保守的RNA结合蛋白，参与多能性和肿瘤发生，先前显示其触发TuT 4介导的pre-let-7尿苷酸化，抑制其加工并靶向其降解。令人惊讶的是，尽管与其他前体microRNA（pre-miRNAs）结合，但只有pre-let-7被TuT 4有效地尿苷化。因此，我们假设存在底物特异性辅因子，其刺激Lin 28 a介导的pre-let-7尿苷酸化或限制其在非let-7 pre-miRNA上的功能。通过RNA下拉结合定量质谱，我们确定了E3连接酶Trim 25作为Lin 28 a/TuT 4介导的尿苷酸化的RNA特异性辅因子。我们发现Trim 25与pre-let-7的保守末端环（CTL）结合并激活TuT 4，从而允许更有效的Lin 28 a介导的尿苷化。这些研究结果表明，蛋白质修饰酶，最近才被证明可以结合RNA，可以指导典型的核糖核蛋白（RNP）复合物的顺式功能，从而提供了额外的特异性水平。E3连接酶Trim 25与pre-let-7的保守末端环结合Trim 25是Lin 28 a/TuT 4介导的尿苷酸化的RNA特异性辅因子Lin 28 a触发TuT 4介导的pre-let-7尿苷酸化。尽管与其他前体microRNA结合，但只有pre-let-7被TuT 4有效地尿苷化。乔杜里等显示Trim 25是Lin 28 a/TuT 4介导尿苷酸化的RNA特异性辅因子。这些发现揭示了Trim 25可以顺式引导典型RNP复合物的功能，从而提供额外水平的特异性。
RNA binding proteins have thousands of cellular RNA targets and often exhibit opposite or passive molecular functions. Lin28a is a conserved RNA binding protein involved in pluripotency and tumorigenesis that was previously shown to trigger TuT4-mediated pre-let-7 uridylation, inhibiting its processing and targeting it for degradation. Surprisingly, despite binding to other pre-microRNAs (pre-miRNAs), only pre-let-7 is efficiently uridylated by TuT4. Thus, we hypothesized the existence of substrate-specific cofactors that stimulate Lin28a-mediated pre-let-7 uridylation or restrict its functionality on non-let-7 pre-miRNAs. Through RNA pull-downs coupled with quantitative mass spectrometry, we identified the E3 ligase Trim25 as an RNA-specific cofactor for Lin28a/TuT4-mediated uridylation. We show that Trim25 binds to the conserved terminal loop (CTL) of pre-let-7 and activates TuT4, allowing for more efficient Lin28a-mediated uridylation. These findings reveal that protein-modifying enzymes, only recently shown to bind RNA, can guide the function of canonical ribonucleoprotein (RNP) complexes in cis, thereby providing an additional level of specificity. Lin28a binding to a pre-miRNA is insufficient to trigger TuT4-mediated uridylation The E3 ligase Trim25 binds to the conserved terminal loop of pre-let-7 Trim25 is an RNA-specific cofactor for Lin28a/TuT4-mediated uridylation Lin28a triggers TuT4-mediated pre-let-7 uridylation. Despite binding to other pre-microRNAs, only pre-let-7 is efficiently uridylated by TuT4. Choudhury et al. show that Trim25 is an RNA-specific cofactor for Lin28a/TuT4-mediated uridylation. These findings reveal that Trim25 can guide the function of canonical RNP complexes in cis, thereby providing an additional level of specificity.