CiRS-7 Enhances the Liquid-liquid Phase Separation of miRISC and Promotes DNA Damage Repair

ABSTRACT

Noncoding RNAs have been found to play important roles in DNA damage repair, whereas the participation of circRNA remains undisclosed. Here, we characterized ciRS-7, a circRNA containing over 70 putative miR-7-binding sites, as an enhancer of miRISC condensation and DNA repair. Both in vivo and in vitro experiments confirmed the condensation of TNRC6B and AGO2, two core protein components of human miRISC. Moreover, overexpressing ciRS-7 largely increased the condensate number of TNRC6B and AGO2 in cells, while silencing ciRS-7 reduced it. Additionally, miR-7 overexpression also promoted miRISC condensation. Consistent with the previous report that AGO2 participated in RAD51-mediated DNA damage repair, the overexpression of ciRS-7 significantly promoted irradiation-induced DNA damage repair by enhancing RAD51 recruitment. Our results uncover a new role of circRNA in liquid-liquid phase separation and provide new insight into the regulatory mechanism of ciRS-7 on miRISC function and DNA repair.

KEYWORDS:

• CircRNA
• ciRS-7
• condensation
• DNA repair
• liquid-liquid phase separation
• miRISC

Acknowledgments

We appreciated the technical support and generous help from Dr. Hao Nan (Northwest A&F University) and Dr. Zhi-Heng Deng (Tsinghua University) on protein purification.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Author contributions

X.B.W. and X.J.F. designed and supervised this study. Y.L.W., L.L.F., J.S., W.Y.C., S.Y.B., S.M.B., G.D.Z. and R.Z.W. performed the experiments. L.L.F., J.S., and Y.L.W. wrote the manuscript. J.Z., X.B.W. and X.J.F. revised the manuscript. All authors read and approved the final manuscript.

Research involving human participants and/or animals

This article does not contain any studies with human participants performed by any of the authors.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19491034.2023.2293599.

Additional information

Funding

The work was supported by the National Key R&D Program of China [2022YFA1105300, 2022YFC2503700]; The National Science Fund for Distinguished Young Scholars [82225040]; the National Science Fund for Excellent Young Scholars [82122057]; the Natural Science Foundation of China [82103770, 81972750, 82373513, 82171163, 82302307]; Guangdong Natural Science Funds for Distinguished Young Scholars [2021B1515020022, 2023B1515020090]; Guangdong Science and Technology Project [2022A1515012363]; Fundamental Research Funds for the Central Universities [22qntd3602]; and the National Postdoctoral Program for Innovative Talents of China [BX20220359]; Beijing Bethune Charitable Foundation [flzh202102].