RAD51AP1 regulates ALT-HDR through chromatin-directed homeostasis of TERRA

Nicole Kaminski; Anne R Wondisford; Youngho Kwon; Michelle Lee Lynskey; Ragini Bhargava; Jonathan Barroso-González; Laura García-Expósito; Boxue He; Meng Xu; Dattatreya Mellacheruvu; Simon C Watkins; Mauro Modesti; Kyle M Miller; Alexey I Nesvizhskii; Huaiying Zhang; Patrick Sung; Roderick J O'Sullivan

doi:10.1016/j.molcel.2022.09.025

RAD51AP1 regulates ALT-HDR through chromatin-directed homeostasis of TERRA

Mol Cell. 2022 Nov 3;82(21):4001-4017.e7. doi: 10.1016/j.molcel.2022.09.025. Epub 2022 Oct 19.

Authors

Nicole Kaminski¹, Anne R Wondisford¹, Youngho Kwon², Michelle Lee Lynskey¹, Ragini Bhargava¹, Jonathan Barroso-González¹, Laura García-Expósito¹, Boxue He³, Meng Xu⁴, Dattatreya Mellacheruvu⁵, Simon C Watkins⁶, Mauro Modesti⁷, Kyle M Miller⁸, Alexey I Nesvizhskii⁵, Huaiying Zhang⁴, Patrick Sung², Roderick J O'Sullivan⁹

Affiliations

¹ Department of Pharmacology and Chemical Biology, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, USA.
² Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA.
³ Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA; Department of Thoracic Surgery, Second Xiangya Hospital, Central South University, Changsha 410011, China.
⁴ Department of Biological Sciences, Mellon College of Science, Carnegie Mellon University, Pittsburgh, PA, USA.
⁵ Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA.
⁶ Department of Cell Biology, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, USA.
⁷ Cancer Research Center of Marseille, CNRS UMR7258, Inserm UMR1068, Aix Marseille Université U105, Institut Paoli Calmettes, 27 Boulevard Lei Roure CS30059, 13273 Marseille Cedex 09, France.
⁸ Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2506 Speedway, Austin, TX 78712, USA.
⁹ Department of Pharmacology and Chemical Biology, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, USA. Electronic address: osullivanr@upmc.edu.

Abstract

Alternative lengthening of telomeres (ALT) is a homology-directed repair (HDR) mechanism of telomere elongation that controls proliferation in subsets of aggressive cancer. Recent studies have revealed that telomere repeat-containing RNA (TERRA) promotes ALT-associated HDR (ALT-HDR). Here, we report that RAD51AP1, a crucial ALT factor, interacts with TERRA and utilizes it to generate D- and R-loop HR intermediates. We also show that RAD51AP1 binds to and might stabilize TERRA-containing R-loops as RAD51AP1 depletion reduces R-loop formation at telomere DNA breaks. Proteomic analyses uncover a role for RAD51AP1-mediated TERRA R-loop homeostasis in a mechanism of chromatin-directed suppression of TERRA and prevention of transcription-replication collisions (TRCs) during ALT-HDR. Intriguingly, we find that both TERRA binding and this non-canonical function of RAD51AP1 require its intrinsic SUMO-SIM regulatory axis. These findings provide insights into the multi-contextual functions of RAD51AP1 within the ALT mechanism and regulation of TERRA.

Keywords: ALT; RAD51AP1; TERRA; cancer; chromatin; homology-directed repair; telomere; transcription.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Chromatin / genetics
Homeostasis
Proteomics
RNA, Long Noncoding* / genetics
Telomere / genetics
Telomere / metabolism
Telomere Homeostasis*

Substances

Chromatin
RNA, Long Noncoding

Abstract

Publication types

MeSH terms

Substances

Grants and funding