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Updated: Dec 6, 2025
Using Next Generation Sequencing to Identify Mutations Associated with Repair of a CAS9-induced Double Strand Break Near the CD4 Promoter
Published on: March 31, 2022
Mechanism of efficient double-strand break repair by a long non-coding RNA
Roopa Thapar1, Jing L Wang2, Michal Hammel3
1Department of Molecular and Cellular Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
Abstract:
Mechanistic studies in DNA repair have focused on roles of multi-protein DNA complexes, so how long non-coding RNAs (lncRNAs) regulate DNA repair is less well understood. Yet, lncRNA LINP1 is over-expressed in multiple cancers and confers resistance to ionizing radiation and chemotherapeutic drugs. Here, we unveil structural and mechanistic insights into LINP1's ability to facilitate non-homologous end joining (NHEJ). We characterized LINP1 structure and flexibility and analyzed interactions with the NHEJ factor Ku70/Ku80 (Ku) and Ku complexes that direct NHEJ. LINP1 self-assembles into phase-separated condensates via RNA-RNA interactions that reorganize to form filamentous Ku-containing aggregates. Structured motifs in LINP1 bind Ku, promoting Ku multimerization and stabilization of the initial synaptic event for NHEJ. Significantly, LINP1 acts as an effective proxy for PAXX. Collective results reveal how lncRNA effectively replaces a DNA repair protein for efficient NHEJ with implications for development of resistance to cancer therapy.
Insights
Long non-coding RNA LINP1 replaces a DNA repair protein, facilitating non-homologous end joining (NHEJ) in cancer cells. This mechanism explains resistance to radiation and chemotherapy, offering new therapeutic targets.
Area of Science:
- Molecular Biology
- Cancer Research
- RNA Biology
Background:
- DNA repair mechanisms are crucial for maintaining genomic stability.
- The role of long non-coding RNAs (lncRNAs) in DNA repair is not fully understood.
- LINP1, a lncRNA overexpressed in cancers, is linked to resistance against radiation and chemotherapy.
Purpose of the Study:
- To elucidate the structural and mechanistic basis of how lncRNA LINP1 facilitates non-homologous end joining (NHEJ).
- To investigate LINP1's interactions with key NHEJ factors.
- To understand LINP1's role in cancer therapy resistance.
Main Methods:
- Structural and flexibility characterization of LINP1.
- Analysis of LINP1 interactions with the Ku70/Ku80 (Ku) complex.
- Investigating LINP1-mediated phase separation and aggregate formation.
- Assessing LINP1's functional role as a PAXX protein proxy.
Main Results:
- LINP1 self-assembles into phase-separated condensates through RNA-RNA interactions.
- LINP1 reorganizes into filamentous aggregates containing the Ku complex.
- Specific structured motifs in LINP1 bind Ku, promoting its multimerization and stabilizing the NHEJ synaptic initiation.
- LINP1 effectively functions as a substitute for the PAXX protein in NHEJ.
Conclusions:
- lncRNA LINP1 plays a direct role in facilitating NHEJ by interacting with the Ku complex.
- LINP1's ability to replace a DNA repair protein (PAXX) contributes to cancer therapy resistance.
- Understanding LINP1's mechanism provides insights into cancer progression and potential therapeutic strategies.
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