Mechanism of spliceosome termination.

Cryo-EM structures reveal that human spliceosome termination involves helicases DHX15, Aquarius, and DHX35, leading to spliceosome disassembly after intron excision.

• Why it matters: Understanding how spliceosomes disassemble after splicing is crucial for insights into gene regulation and preventing errors in mRNA processing, yet the exact mechanism was previously unknown.
• What they did: The study used cryo-electron microscopy to capture spliceosome structures at two stages of termination, showing how helicases unwind RNA, debranch the intron, and eject it to disassemble the spliceosome.
• The result: This work clarifies the molecular steps of spliceosome termination, highlighting parallels with quality control, and enables potential targeting of splicing errors in disease contexts.