MicroRNA-mediated gene silencing modulates the UV-induced DNA-damage response
Supplementary Material
Supplementary Figure S1
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Supplementary Material and Methods
Review Process File
Abstract
DNA damage provokes DNA repair, cell-cycle regulation and apoptosis. This DNA-damage response encompasses gene-expression regulation at the transcriptional and post-translational levels. We show that cellular responses to UV-induced DNA damage are also regulated at the post-transcriptional level by microRNAs. Survival and checkpoint response after UV damage was severely reduced on microRNA-mediated gene-silencing inhibition by knocking down essential components of the microRNA-processing pathway (Dicer and Ago2). UV damage triggered a cell-cycle-dependent relocalization of Ago2 into stress granules and various microRNA-expression changes. Ago2 relocalization required CDK activity, but was independent of ATM/ATR checkpoint signalling, whereas UV-responsive microRNA expression was only partially ATM/ATR independent. Both microRNA-expression changes and stress-granule formation were most pronounced within the first hours after genotoxic stress, suggesting that microRNA-mediated gene regulation operates earlier than most transcriptional responses. The functionality of the microRNA response is illustrated by the UV-inducible miR-16 that downregulates checkpoint-gene CDC25a and regulates cell proliferation. We conclude that microRNA-mediated gene regulation adds a new dimension to the DNA-damage response.
Acknowledgments
We thank P Sharp and A Leung for providing the GFP–Ago2 expression vector and G Hannon and E Murchison for dicer-deficient ES cells. We thank T Boersma, P Kuijk and K Kockx for technical assistance. We thank the Hoeijmakers lab for critical discussions. This study was supported by the Association for International Cancer Research (AICR grant 05-135), the Dutch Cancer Foundation KWF (EMCR 2007-3794), the Netherlands Scientific Organization for Biomedical Research (ZonMW, Veni 016-076-069), Netherlands Genomics Initiative grant nr 050-060-510 and the European Commission (projects DNA Repair (LSHG-CT-2005-512113) and RIBOREG (LSHG-CT-2003-503022).
Footnotes
JHJH is the Chief Scientific Officer of DNage/Pharming. The other authors declare that they have no conflict of interest.