EWS-FLI1 employs an E2F switch to drive target gene expression.

Abstract

Cell cycle progression is orchestrated by E2F factors. We previously reported that in ETS-driven cancers of the bone and prostate, activating E2F3 cooperates with ETS on target promoters. The mechanism of target co-regulation remained unknown. Using RNAi and time-resolved chromatin-immunoprecipitation in Ewing sarcoma we report replacement of E2F3/pRB by constitutively expressed repressive E2F4/p130 complexes on target genes upon EWS-FLI1 modulation. Using mathematical modeling we interrogated four alternative explanatory models for the observed EWS-FLI1/E2F3 cooperation based on longitudinal E2F target and regulating transcription factor expression analysis. Bayesian model selection revealed the formation of a synergistic complex between EWS-FLI1 and E2F3 as the by far most likely mechanism explaining the observed kinetics of E2F target induction. Consequently we propose that aberrant cell cycle activation in Ewing sarcoma is due to the de-repression of E2F targets as a consequence of transcriptional induction and physical recruitment of E2F3 by EWS-FLI1 replacing E2F4 on their target promoters.

• Authors: Raphaela Schwentner, Theodore Papamarkou, Maximilian O Kauer, Vassilios Stathopoulos, Fan Yang, Sven Bilke, Paul S Meltzer, Mark Girolami, Heinrich Kovar
• Journal: Nucleic acids research (Nucleic Acids Res) Vol. 43 Issue 5 Pg. 2780-9 (Mar 11 2015) ISSN: 1362-4962 [Electronic] England
• PMID: 25712098 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Chemical References

• E2F3 Transcription Factor
• E2F3 protein, human
• E2F4 Transcription Factor
• E2F4 protein, human
• EWS-FLI fusion protein
• Oncogene Proteins, Fusion
• Proto-Oncogene Protein c-fli-1
• RNA-Binding Protein EWS

Topics

• Algorithms
• Bayes Theorem
• Cell Cycle (genetics)
• Cell Line, Tumor
• Chromatin Immunoprecipitation
• E2F3 Transcription Factor (genetics, metabolism)
• E2F4 Transcription Factor (genetics, metabolism)
• Gene Expression Regulation, Neoplastic
• Humans
• Immunoblotting
• Models, Genetic
• Oncogene Proteins, Fusion (genetics, metabolism)
• Promoter Regions, Genetic (genetics)
• Protein Binding
• Proto-Oncogene Protein c-fli-1 (genetics, metabolism)
• RNA Interference
• RNA-Binding Protein EWS (genetics, metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Sarcoma, Ewing (genetics, metabolism, pathology)