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Updated: Jul 8, 2025
11:52
Analysis of LINE-1 Retrotransposition at the Single Nucleus Level
Published on: April 23, 2016
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Structures, functions and adaptations of the human LINE-1 ORF2 protein
Eric T Baldwin1, Trevor van Eeuwen2, David Hoyos3
1ROME Therapeutics, Boston, MA, USA.
Nature
|December 14, 2023
Summary
LINE-1 retrotransposons copy and paste DNA using ORF2p enzyme. New structures reveal its mechanisms, enabling therapeutic targeting for diseases like cancer and autoimmune disorders.
Area of Science:
- Molecular Biology
- Genetics
- Structural Biology
Background:
- LINE-1 (L1) retrotransposons comprise a significant portion of the human genome.
- The L1 open reading frame 2 protein (ORF2p) is crucial for L1 retrotransposition.
- ORF2p's roles in cancer, autoimmunity, and aging highlight its therapeutic potential, yet structural insights are lacking.
Purpose of the Study:
- To elucidate the structure and mechanism of the human ORF2p.
- To identify potential therapeutic targets for L1-associated diseases.
Main Methods:
- X-ray crystallography and cryo-electron microscopy to determine ORF2p core structures.
- Integrative structural modeling for full-length ORF2p.
- Biochemical assays and imaging to characterize ORF2p activities and interactions.
Main Results:
- Revealed novel folded domains within ORF2p and its extensive RNA template interactions.
- Identified a dynamic closed-ring conformation of full-length ORF2p that opens during retrotransposition.
- Characterized ORF2p reverse transcriptase inhibition and its structural basis, including non-canonical activity triggering innate immunity.
Conclusions:
- Provided key mechanistic insights into L1 polymerization and insertion.
- Established structural conservation between ORF2p and other polymerases, shedding light on L1 evolution.
- Enabled rational drug development targeting L1 for therapeutic applications.
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