Characterization of the mechanism by which the RB/E2F pathway controls expression of the cancer genomic DNA deaminase APOBEC3B
- University of Minnesota, United States
- National University of Singapore, Singapore
- Howard Hughes Medical Institute, University of Minnesota, United States
- Erasmus MC Cancer Institute, Erasmus University Medical Center, Netherlands
- Radboud University Medical Center, Netherlands [NL]
Abstract
APOBEC3B (A3B)-catalyzed DNA cytosine deamination contributes to the overall mutational landscape in breast cancer. Molecular mechanisms responsible for A3B upregulation in cancer are poorly understood. Here, we show that a single E2F cis-element mediates repression in normal cells and that expression is activated by its mutational disruption in a reporter construct or the endogenous A3B gene. The same E2F site is required for A3B induction by polyomavirus T antigen indicating a shared molecular mechanism. Proteomic and biochemical experiments demonstrate binding of wildtype but not mutant E2F promoters by repressive PRC1.6/E2F6 and DREAM/E2F4 complexes. Knockdown and overexpression studies confirm involvement of these repressive complexes in regulating A3B expression. Altogether, these studies demonstrate that A3B expression is suppressed in normal cells by repressive E2F complexes and that viral or mutational disruption of this regulatory network triggers overexpression in breast cancer and provides fuel for tumor evolution.
Data availability
Raw mass spectrometry data will be accessible through the ProteomeXchange Consortium via the PRIDE (Vizcaino et al., 2016) partner repository with the dataset identifier PXD020473. Additional data generated or analysed during this study are included in the manuscript and supporting files.
Article and author information
Author details
Funding
National Cancer Institute (P01-CA234228)
- Reuben S Harris
KWF Kankerbestrijding (KWF10270)
- John WM Martens
- Paul N Span
- Reuben S Harris
National Research Foundation Singapore (NMRC/OFYIRG/055/2017)
- Dennis Kappei
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Roelofs et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Characterization of the mechanism by which the RB/E2F pathway controls expression of the cancer genomic DNA deaminase APOBEC3B
eLife 9:e61287.
https://doi.org/10.7554/eLife.61287
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