Promyelocytic leukemia nuclear bodies are predetermined processing sites for damaged DNA.
The promyelocytic leukemia protein (PML) participates in several cellular functions, including transcriptional regulation, apoptosis and maintenance of genomic stability. A key feature of this protein is its ability to induce the assembly of nuclear compartments termed PML-nuclear bodies (PML-NBs). Here we show that these nuclear structures recruit single-stranded DNA (ssDNA) molecules in response to exogenous DNA damage. ssDNA was readily detected in PML-NBs within 1 hour following exposure of cells to UV light. Confocal real-time imaging of cells expressing YFP-tagged PML did not reveal de novo formation of new PML-NBs following UV-irradiation, which shows that ssDNA focus formation occurred within pre-existing PML-NBs. Moreover, siRNA-mediated depletion of PML prevented ssDNA focus formation and sensitized cells to UV-induced apoptosis. PML-dependent ssDNA focus formation was found to be particularly efficient during S-phase of the cell cycle, and PML-depleted cells became retarded in S-phase upon growth in the presence of etoposide. In addition, we found that caffeine and the poly(ADP-ribose) polymerase (PARP) inhibitor NU1027 enhanced UV-induced recruitment of ssDNA to PML-NBs. Together, our results show that PML-NBs have the capacity to accommodate DNA metabolic activities that are associated with processing of damaged DNA.
Bøe
Stig Ove
SO
Section of Oncology, Department of Medicine, Haukeland University Hospital, Bergen, Norway. stig.boe@vir.uib.no
Haave
Marte
M
Jul-Larsen
Asne
A
Grudic
Amra
A
Bjerkvig
Rolf
R
Lønning
Per Eystein
PE
D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002110:Caffeine / Q000494:pharmacology; D022003:Cell Nucleus Structures / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects*; D004260:DNA Repair; D004273:DNA, Neoplasm / Q000235:genetics / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000071156:Promyelocytic Leukemia Protein; D034741:RNA, Small Interfering / Q000494:pharmacology; D016196:S Phase / Q000187:drug effects / Q000528:radiation effects; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays; D014471:Umbilical Veins / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D016335:Zinc Fingers
D000697:Central Nervous System Stimulants; D004273:DNA, Neoplasm; D004277:DNA, Single-Stranded; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000071156:Promyelocytic Leukemia Protein; D034741:RNA, Small Interfering; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C070576:PML protein, human; D002110:Caffeine