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UV-C-induced DNA damage leads to p53-dependent nuclear trafficking of PML
Hasan Seker1, Carlos Rubbi, Steven P Linke
1Laboratory of Human Carcinogenesis, CCR, National Cancer Institute, NIH, Bethesda, MD 20892-4255, USA.
Abstract:
The promyelocytic leukemia protein (PML) is a nuclear phosphoprotein that localizes to distinct domains in the nucleus, described as PML nuclear bodies (PML-NBs). Recent findings indicate that PML regulates the p53 response to oncogenic signals. Here, we define a p53-dependent role for PML in response to DNA damage. We exposed cells to ultraviolet light (UV-C) and imaged the nuclear distribution of PML, p53, and the BLM helicase by confocal microscopy. After DNA damage, PML partially relocated out of the PML-NBs, and colocalized with BLM and p53 at sites of DNA repair. In addition, using the isogenic HCT116 cell lines (p53+/+ and -/-), we show that the redistribution of PML was dependent on functional p53. Western analysis revealed that the level of PML protein remained unaltered after UV-C treatment. These results are consistent with the hypothesis that PML, in conjunction with p53 and BLM, contributes to the cellular response to UV-C-induced DNA damage and its repair.
Insights
The promyelocytic leukemia protein (PML) relocates to DNA damage sites, working with p53 and BLM to repair UV-C damage. This PML function is dependent on functional p53.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- The promyelocytic leukemia protein (PML) forms nuclear bodies (PML-NBs) and is implicated in the p53 response to oncogenic signals.
- Understanding PML's role in DNA damage response is crucial for cellular integrity.
Purpose of the Study:
- To define a p53-dependent role for PML in the cellular response to DNA damage.
- To investigate the dynamic localization of PML, p53, and BLM helicase following UV-C exposure.
Main Methods:
- Confocal microscopy was used to image the nuclear distribution of PML, p53, and BLM in cells exposed to UV-C radiation.
- Isogenic HCT116 cell lines (p53+/+ and p53-/-) were utilized to assess p53 dependency.
- Western blot analysis was performed to evaluate changes in PML protein levels.
Main Results:
- Following UV-C treatment, PML partially relocated from PML-NBs and colocalized with BLM and p53 at DNA repair sites.
- PML redistribution was dependent on the presence of functional p53, as demonstrated in isogenic cell lines.
- UV-C exposure did not alter the overall level of PML protein.
Conclusions:
- PML plays a p53-dependent role in the cellular response to UV-C-induced DNA damage.
- PML, p53, and BLM likely collaborate in the DNA repair process after UV-C exposure.