Dysregulated pre-mRNA splicing is an emerging Achilles heel of cancers and myelodysplasias. To expand the currently limited portfolio of small molecule drug leads, we screened for chemical modulators of the U2AF complex, which nucleates spliceosome assembly and is mutated in myelodysplasias. A hit compound specifically enhanced RNA binding by a U2AF2 subunit. Remarkably, the compound inhibits splicing of representative substrates in cells and stalls spliceosome assembly at the stage of U2AF function. In silico docking, together with structure-guided mutagenesis, indicates that the compound bridges an active conformation of the U2AF2 RNA recognition motifs via hydrophobic and electrostatic moieties. Altogether, our results highlight the potential of trapping early spliceosome assembly as an effective pharmacological means to manipulate pre-mRNA splicing. By extension, we suggest that stabilizing inactive checkpoints may offer a breakthrough approach for small molecule inhibition of multi-stage macromolecular assemblies.

中文翻译：

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合成的小分子通过促进早期的U2AF2-RNA复合物来阻止前mRNA剪接

失调的mRNA前融合是癌症和骨髓增生异常的新兴致命弱点。为了扩展目前有限的小分子药物线索组合，我们筛选了U2AF复合物的化学调节剂，该复合物使剪接体组装成核并在骨髓增生异常中发生突变。命中化合物特异性增强了U2AF2亚基与RNA的结合。值得注意的是，该化合物在U2AF功能阶段抑制细胞中代表性底物的剪接，并使剪接体组装失速。计算机对接以及结构指导的诱变表明，该化合物通过疏水和静电部分桥接了U2AF2 RNA识别基序的活性构象。共，我们的结果突出了捕获早期剪接体装配作为操作前mRNA剪接的有效药理学方法的潜力。通过扩展，我们建议稳定非活动检查点可能为多阶段大分子组装体的小分子抑制提供突破性方法。