Structural mechanism of LINE-1 target-primed reverse transcription

• 成果类型: Article
• 署名作者: Ghanim, George E.; Hu, Hongmiao; Boulanger, Jerome; Thi Hoang Duong Nguyen
• 署名单位: MRC Laboratory Molecular Biology
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-10902
• DOI: 10.1126/science.ads8412
• 发表日期: 2025-04-25
• 关键词: poly(a) binding-protein; messenger-rna deadenylation; human l1 retrotransposition; cryo-em structure; poly(a)-binding protein; tail length; dna; refinement; ELEMENTS; endonuclease

摘要

Long interspersed element-1 (LINE-1) retrotransposons are the only active autonomous transposable elements in humans. They propagate by reverse transcribing their messenger RNA into new genomic locations by a process called target-primed reverse transcription (TPRT). In this work, we present four cryo-electron microscopy structures of the human LINE-1 TPRT complex, revealing the conformational dynamics of open reading frame 2 protein (ORF2p) and its extensive remodeling of the target DNA for TPRT initiation. We observe nicking of the DNA second strand during reverse transcription of the first strand. Structure prediction identifies high-confidence binding sites for LINE-1-associated factors-namely proliferating cell nuclear antigen (PCNA) and cytoplasmic poly(A)-binding protein 1 (PABPC1)-on ORF2p. Together with our structural data, this suggests a mechanism by which these factors regulate retrotransposition and supports a model for TPRT that accounts for retrotransposition outcomes observed in cells.