@article{TrifaultMamontovaCossaetal.2024, author = {Trifault, Barbara and Mamontova, Victoria and Cossa, Giacomo and Ganskih, Sabina and Wei, Yuanjie and Hofstetter, Julia and Bhandare, Pranjali and Baluapuri, Apoorva and Nieto, Blanca and Solvie, Daniel and Ade, Carsten P. and Gallant, Peter and Wolf, Elmar and Larsen, Dorthe H. and Munschauer, Mathias and Burger, Kaspar}, title = {Nucleolar detention of NONO shields DNA double-strand breaks from aberrant transcripts}, series = {Nucleic Acids Research}, volume = {52}, journal = {Nucleic Acids Research}, number = {6}, doi = {10.1093/nar/gkae022}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350208}, pages = {3050-3068}, year = {2024}, abstract = {RNA-binding proteins emerge as effectors of the DNA damage response (DDR). The multifunctional non-POU domain-containing octamer-binding protein NONO/p54\(^{nrb}\) marks nuclear paraspeckles in unperturbed cells, but also undergoes re-localization to the nucleolus upon induction of DNA double-strand breaks (DSBs). However, NONO nucleolar re-localization is poorly understood. Here we show that the topoisomerase II inhibitor etoposide stimulates the production of RNA polymerase II-dependent, DNA damage-inducible antisense intergenic non-coding RNA (asincRNA) in human cancer cells. Such transcripts originate from distinct nucleolar intergenic spacer regions and form DNA-RNA hybrids to tether NONO to the nucleolus in an RNA recognition motif 1 domain-dependent manner. NONO occupancy at protein-coding gene promoters is reduced by etoposide, which attenuates pre-mRNA synthesis, enhances NONO binding to pre-mRNA transcripts and is accompanied by nucleolar detention of a subset of such transcripts. The depletion or mutation of NONO interferes with detention and prolongs DSB signalling. Together, we describe a nucleolar DDR pathway that shields NONO and aberrant transcripts from DSBs to promote DNA repair.}, language = {en} } @article{TrifaultMamontovaBurger2022, author = {Trifault, Barbara and Mamontova, Victoria and Burger, Kaspar}, title = {In vivo proximity labeling of nuclear and nucleolar proteins by a stably expressed, DNA damage-responsive NONO-APEX2 fusion protein}, series = {Frontiers in Molecular Biosciences}, volume = {9}, journal = {Frontiers in Molecular Biosciences}, issn = {2296-889X}, doi = {10.3389/fmolb.2022.914873}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-276707}, year = {2022}, abstract = {Cellular stress can induce DNA lesions that threaten the stability of genes. The DNA damage response (DDR) recognises and repairs broken DNA to maintain genome stability. Intriguingly, components of nuclear paraspeckles like the non-POU domain containing octamer-binding protein (NONO) participate in the repair of DNA double-strand breaks (DSBs). NONO is a multifunctional RNA-binding protein (RBP) that facilitates the retention and editing of messenger (m)RNA as well as pre-mRNA processing. However, the role of NONO in the DDR is poorly understood. Here, we establish a novel human U2OS cell line that expresses NONO fused to the engineered ascorbate peroxidase 2 (U2OS:NONO-APEX2-HA). We show that NONO-APEX2-HA accumulates in the nucleolus in response to DNA damage. Combining viability assays, subcellular localisation studies, coimmunoprecipitation experiments and in vivo proximity labeling, we demonstrate that NONO-APEX2-HA is a stably expressed fusion protein that mimics endogenous NONO in terms of expression, localisation and bona fide interactors. We propose that in vivo proximity labeling in U2OS:NONO-APEX2-HA cells is capable for the assessment of NONO interactomes by downstream assays. U2OS:NONO-APEX2-HA cells will likely be a valuable resource for the investigation of NONO interactome dynamics in response to DNA damage and other stimuli.}, language = {en} }