Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14620, USA.
Department of Chemistry, University of Rochester, Rochester, NY 14627, USA.
Cell Chem Biol. 2021 Aug 19;28(8):1145-1157.e6. doi: 10.1016/j.chembiol.2021.02.007. Epub 2021 Mar 8.
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 enhances RNA binding by a U2AF2 subunit. Remarkably, the compound inhibits splicing of representative substrates and stalls spliceosome assembly at the stage of U2AF function. Computational docking, together with structure-guided mutagenesis, indicates that the compound bridges the tandem U2AF2 RNA recognition motifs via hydrophobic and electrostatic moieties. Cells expressing a cancer-associated U2AF1 mutant are preferentially killed by treatment with the compound. 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 assembly intermediates may offer a useful approach for small-molecule inhibition of macromolecular machines.
mRNA 前体剪接失调是癌症和骨髓增生异常的新兴致命弱点。为了扩大目前有限的小分子药物先导物组合，我们筛选了 U2AF 复合物的化学调节剂，该复合物启动剪接体组装，并且在骨髓增生异常中发生突变。一个命中化合物特异性地增强了 U2AF2 亚基的 RNA 结合。值得注意的是，该化合物抑制代表性底物的剪接，并使剪接体组装在 U2AF 功能阶段停滞。计算对接，以及结构指导的诱变，表明该化合物通过疏水性和静电部分桥接串联的 U2AF2 RNA 识别基序。用该化合物处理表达癌症相关 U2AF1 突变体的细胞会被优先杀死。总之，我们的研究结果强调了捕获早期剪接体组装作为一种有效药理学手段来操纵 pre-mRNA 剪接的潜力。由此，我们提出稳定组装中间体可能是抑制大分子机器的小分子抑制的一种有用方法。
