BGL3 lncRNA mediates retention of the BRCA1/BARD1 complex at DNA damage sites

• Published in: The EMBO journal 2020-06, Vol.39 (12), p.e104133-n/a
• Main Authors: Hu, Zhaohua, Mi, Shaojie, Zhao, Ting, Peng, Changmin, Peng, Yihan, Chen, Lulu, Zhu, Wenge, Yao, Yi, Song, Qibin, Li, Xiangpan, Li, Xinzhi, Jia, Chenxi, Pei, Huadong
• Format: Article
• Language: English
• Subjects: Amino acids; Antisense RNA; BGL3; Binding; BRCA1 protein; BRCA1 Protein - genetics; BRCA1 Protein - metabolism; BRCA1/BARD1; Breast cancer; Control stability; Coupling (molecular); Damage accumulation; Deoxyribonucleic acid; Depletion; DNA; DNA Breaks, Double-Stranded; DNA Damage; DNA repair; Domains; EMBO13; EMBO36; Genomic instability; Genomics; HEK293 Cells; Homologous recombination; homologous recombination repair; Homology; Humans; LncRNA; Mass spectrometry; Mass spectroscopy; MCF-7 Cells; Molecular modelling; Multiprotein Complexes - genetics; Multiprotein Complexes - metabolism; Non-coding RNA; Poly (ADP-Ribose) Polymerase-1 - genetics; Poly (ADP-Ribose) Polymerase-1 - metabolism; Poly(ADP-ribose) polymerase; Protein Domains; Purification; Reagents; Regulators; Retention; Ribonucleic acid; RNA; RNA, Long Noncoding - genetics; RNA, Long Noncoding - metabolism; Scientific imaging; Spectroscopy; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - metabolism
• ISSN: 0261-4189; 1460-2075
• DOI: 10.15252/embj.2019104133

Long non‐coding RNAs (lncRNAs) are emerging regulators of genomic stability and human disease. However, the molecular mechanisms by which nuclear lncRNAs directly contribute to DNA damage responses remain largely unknown. Using RNA antisense purification coupled with quantitative mass spectrometry (RAP‐qMS), we found that the lncRNA BGL3 binds to PARP1 and BARD1, exhibiting unexpected roles in homologous recombination. Mechanistically, BGL3 is recruited to DNA double‐strand breaks (DSBs) by PARP1 at an early time point, which requires its interaction with the DNA‐binding domain of PARP1. BGL3 also binds the C‐terminal BRCT domain and an internal region (amino acids 127–424) of BARD1, which mediates interaction of the BRCA1/BARD1 complex with its binding partners such as HP1γ and RAD51, resulting in BRCA1/BARD1 retention at DSBs. Cells depleted for BGL3 displayed genomic instability and were sensitive to DNA‐damaging reagents. Overall, our findings underscore the biochemical versatility of RNA as a mediator molecule in the DNA damage response pathway, which affects the accumulation of BRCA1/BARD1 at DSBs. Synopsis RNA antisense purification coupled with quantitative mass spectrometry (RAP‐qMS) reveals a surprising role for the lncRNA BGL3 in homologous recombination (HR) repair of DNA double strand breaks (DSBs). BGL3 mediates retention of the BRCA1/BARD1 complex at DNA damage sites, and controls DNA end resection. BGL3 depletion causes genomic instability and sensitizes to DNA damage. BGL3 binds BARD1 and mediates interaction of the BRCA1/BARD1 complex with binding partners such as HP1γ and RAD51, resulting in BRCA1/BARD1 retention at DSBs. BGL3 is recruited to DNA damage sites by PARP1 at an early time point, while BGL3 retention at a late time point depends on the BARD1‐HP1 axis. Graphical Abstract A PARP1‐recruited ncRNA is involved in interactions between BRCA1, RAD51 and HP1 during homologous recombination repair of DNA double strand breaks.