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Updated: Jan 19, 2026
Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry
Published on: June 26, 2019
Dynamic PML protein nucleolar associations with persistent DNA damage lesions in response to nucleolar stress and
Terezie Imrichova1, Sona Hubackova1,2, Alena Kucerova1
1Department of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.
Abstract:
Diverse stress insults trigger interactions of PML with nucleolus, however, the function of these PML nucleolar associations (PNAs) remains unclear. Here we show that during induction of DNA damage-induced senescence in human non-cancerous cells, PML accumulates at the nucleolar periphery simultaneously with inactivation of RNA polymerase I (RNAP I) and nucleolar segregation. Using time-lapse and high-resolution microscopy, we followed the genesis, structural transitions and destiny of PNAs to show that: 1) the dynamic structural changes of the PML-nucleolar interaction are tightly associated with inactivation and reactivation of RNAP I-mediated transcription, respectively; 2) the PML-nucleolar compartment develops sequentially under stress and, upon stress termination, it culminates in either of two fates: disappearance or persistence; 3) all PNAs stages can associate with DNA damage markers; 4) the persistent, commonly long-lasting PML multi-protein nucleolar structures (PML-NDS) associate with markers of DNA damage, indicating a role of PNAs in persistent DNA damage response characteristic for senescent cells. Given the emerging evidence implicating PML in homologous recombination-directed DNA repair, we propose that PNAs contribute to sequestration and faithful repair of the highly unstable ribosomal DNA repeats, a fundamental process to maintain a precise balance between DNA repair mechanisms, with implications for genomic integrity and aging.
Insights
Diverse stress triggers PML nucleolar associations (PNAs), which are linked to DNA damage response and senescence. These structures may aid in repairing ribosomal DNA, maintaining genomic integrity and influencing aging.
Area of Science:
- Cell Biology
- Molecular Biology
- Genomics
Background:
- Diverse stress insults induce interactions between PML protein and the nucleolus, forming PML nucleolar associations (PNAs).
- The precise function of PNAs in cellular stress responses, particularly during DNA damage-induced senescence, remains largely undetermined.
- PML protein is increasingly recognized for its role in DNA repair pathways, including homologous recombination.
Purpose of the Study:
- To elucidate the functional role of PML nucleolar associations (PNAs) during DNA damage-induced senescence.
- To investigate the dynamic structural changes and fate of PNAs in response to cellular stress.
- To explore the association of PNAs with DNA damage markers and their potential role in ribosomal DNA repair.
Main Methods:
- Time-lapse and high-resolution microscopy were employed to observe the formation, structural transitions, and resolution of PNAs.
- Cells were subjected to DNA damage-inducing conditions to trigger senescence.
- Immunofluorescence staining was used to detect PML, DNA damage markers, and assess nucleolar structure.
Main Results:
- PML accumulates at the nucleolar periphery during DNA damage-induced senescence, coinciding with RNA polymerase I (RNAP I) inactivation and nucleolar segregation.
- Dynamic structural changes of PNAs correlate with the inactivation and reactivation of RNAP I transcription.
- PNAs exhibit distinct fates upon stress termination, either disappearing or persisting as long-lasting PML multi-protein nucleolar structures (PML-NDS).
- All stages of PNAs associate with DNA damage markers, with persistent PML-NDS specifically linked to markers of DNA damage in senescent cells.
Conclusions:
- PML nucleolar associations (PNAs) are dynamic structures involved in the cellular response to DNA damage and senescence.
- Persistent PML-NDS are associated with DNA damage, suggesting a role in maintaining genomic integrity during prolonged stress.
- PNAs may contribute to the sequestration and repair of ribosomal DNA repeats, impacting genomic stability and aging processes.
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