Introns are excised from pre-messenger RNAs by the spliceosome, which produces mRNAs with continuous protein-coding information. In humans, most pre-mRNAs undergo alternative splicing to expand proteomic diversity. Cryo-electron microscopy (cryo-EM) structures of the yeast spliceosome elucidated how proteins stabilize and remodel an RNA-based active site to effect splicing catalysis. More recent cryo-EM snapshots of the human spliceosome reveal a complex protein scaffold and provide insights into the role of specific human proteins in modulating spliceosome activation, splice site positioning, and the ATPase-mediated dynamics of the active site. The emerging molecular picture highlights how, compared to its yeast counterpart, the human spliceosome has coopted additional protein factors to allow increased plasticity of splice site recognition and remodeling, and potentially to regulate alternative splicing.

剪接体从前信使 RNA 中切除内含子，剪接体产生具有连续蛋白质编码信息的 mRNA。在人类中，大多数前体 mRNA 经历选择性剪接以扩大蛋白质组学多样性。酵母剪接体的冷冻电子显微镜 (cryo-EM) 结构阐明了蛋白质如何稳定和重塑基于 RNA 的活性位点以影响剪接催化。最近的人类剪接体的冷冻电镜快照揭示了一个复杂的蛋白质支架，并提供了对特定人类蛋白质在调节剪接体激活、剪接位点定位和 ATP 酶介导的活性位点动力学中的作用的见解。新出现的分子图突出了与酵母对应物相比，