Visualization and quantification of rDNA instabilities in mammalian cells and mouse models.

Xiaolu Zhu; Wenxia Jiang; Wei Wu; Brian J Lee; Demis Menolfi; Anthony Tubbs; Olivia M Cupo; Eli Malkovskiy; Mattie Nester; Xiaobin S Wang; Peter A Sims; Chyuan-Sheng V Lin; Lorraine Symington; Andre Nussenzweig; Brian McStay; Shan Zha

doi:10.1093/nar/gkaf1523

PubMed · 41533570

Visualization and quantification of rDNA instabilities in mammalian cells and mouse models.

Xiaolu Zhu·Wenxia Jiang·Wei Wu·Brian J Lee·Demis Menolfi·Anthony Tubbs·Olivia M Cupo·Eli Malkovskiy·Mattie Nester·Xiaobin S Wang·Peter A Sims·Chyuan-Sheng V Lin·Lorraine Symington·Andre Nussenzweig·Brian McStay·Shan Zha

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Abstract

Ribosomal DNA (rDNA) encodes the 18S, 5.8S, and 28S rRNA, accounting for ∼70% of cellular transcription. Despite its essential role and links to cancer and aging, quantifying rDNA instability in mammals remains challenging due to its repetitive organization and inherent heterogeneity. Here, we developed a murine rDNA FISH probe and genomic tools tailored for laboratory mouse strains. The results confirmed rDNA cluster locations, revealed substantial inter- and intra-strain as well as intercellular heterogeneity in rDNA organization within inbred mice and unstressed cells, and identified sources of spontaneous and replication-associated DNA double-strand breaks in the rDNA transcription termination region. Using mouse embryonic stem cells, we showed that BRCA1-mediated homologous recombination promotes rDNA instability, the non-homologous end joining factor XRCC1, but not Ku, suppresses intra-cluster deletions, and ATM kinase preserves rDNA cluster stability. Together, these findings establish a platform and tools for studying rDNA instability in animal models relevant to aging and cancer research.

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Animals Mice Male Female DNA, Ribosomal In Situ Hybridization, Fluorescence Genomics Models, Animal Multigene Family Homologous Recombination Humans Ataxia Telangiectasia Mutated Proteins DNA Breaks, Double-Stranded Journal Article

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Xiaolu Zhu, Wenxia Jiang, Wei Wu, Brian J Lee, Demis Menolfi, Anthony Tubbs, Olivia M Cupo, Eli Malkovskiy, Mattie Nester, Xiaobin S Wang, Peter A Sims, Chyuan-Sheng V Lin, Lorraine Symington, Andre Nussenzweig, Brian McStay, Shan Zha. 2026-01-14. Visualization and quantification of rDNA instabilities in mammalian cells and mouse models.. https://doi.org/10.1093/nar%2Fgkaf1523

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