Dynamic PML protein nucleolar associations with persistent DNA damage lesions in response to nucleolar stress and senescence-inducing stimuli

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.

Ionizing Radiation and Complex DNA Damage: From Prediction to Detection Challenges and Biological Significance

“…The reader may refer to the review by Schermelleh et al [102] for detailed information regarding SRM. Key SRM applications for DNA damage detection can be found in [103,104,105,106,107,108,109,110]. SRM resolution is ~100 nm axial and ~300 nm lateral, while it costs several hundreds of k USD.…”

Dual signaling via interferon and DNA damage response elicits entrapment by giant PML nuclear bodies

“…While most studies that implicate PML-NBs in the DNA damage response have focused on acute cellular DNA damage, very recent data postulate a role in the repair of persistent DNA damage and even show an association of circular PML structures with such DNA lesions 29, 45 . These PML structures occur after prolonged treatment with DNA damage-inducing agents 29 , which fits to our observations (Fig. 4h) and also to the slow kinetics of PML cages biogenesis in HCMVΔIE1-infected cells (Fig.…”

“…4e, f), suggesting that IFN-based upregulation of PML-NB proteins is not sufficient to induce these structures but that a further stimulus is required which is provided by the virus. Since rearrangements of PML-NBs have recently been linked to cellular DNA damage, we speculated that DNA damage signaling, induced by incoming HCMV DNA, is required in addition to IFN signaling 29 . To test this, HFF were treated with IFN or were mock treated, and DNA damage was induced by addition of topoisomerase I inhibitor camptothecin (CPT) or topoisomerase II inhibitor doxorubicin (Doxo).…”

Pirh2-dependent DNA damage in neurons induced by the G-quadruplex ligand pyridostatin

“…We conclude that, in the neuronal nucleus, Pirh2 was enriched in the nucleoli, which often communicate with the PML bodies. The nucleolus and PML bodies communicate and exchange protein factors with each other especially when the cell is stressed (e.g., during DNA damage) (55).…”