Abstract
The transcriptional repressor E2F6 has been identified as a component of two distinct polycomb group protein (PcG)-containing complexes, suggesting a mechanism for the recruitment of repressive complexes to target sequences in DNA. Whereas one complex is involved in the repression of classic E2F target genes in G0, a role for E2F6 within the cell cycle has yet to be defined. We searched for novel E2F6-binding proteins using a yeast two-hybrid screen and identified the PcG protein, EPC1. We showed that, both in vitro and in vivo, E2F6, DP1, and EPC1 form a stable core complex with repressive activity. Furthermore, we identified the proliferation-specific PcG, EZH2, as an EPC1-interacting protein. Using affinity purification, we showed that E2F6, DP1, EPC1, EZH2, and Sin3B co-elute, suggesting the identification of a novel E2F6 complex that exists in vivo in both normal and transformed human cell lines. EZH2 is required for cellular proliferation and consistent with this, EZH2 elutes with the E2F6-EPC1 complex only in proliferating cells. Thus we have identified a novel E2F6-PcG complex (E2F6-EPC1) that interacts with EZH2 and may regulate genes required for cell cycle progression.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Cycle Proteins / chemistry
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cell Line
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Cell Proliferation
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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E2F Transcription Factors
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E2F6 Transcription Factor
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Enhancer of Zeste Homolog 2 Protein
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Histone-Lysine N-Methyltransferase
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Humans
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Mice
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Multiprotein Complexes / chemistry
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Multiprotein Complexes / genetics
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Multiprotein Complexes / isolation & purification
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Multiprotein Complexes / metabolism
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Polycomb Repressive Complex 2
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Polycomb-Group Proteins
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Promoter Regions, Genetic / genetics
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Protein Binding
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Proteins / genetics
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Proteins / metabolism*
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
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Substrate Specificity
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Transcription Factor DP1
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Transcription Factors / chemistry
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Two-Hybrid System Techniques
Substances
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Cell Cycle Proteins
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DNA-Binding Proteins
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E2F Transcription Factors
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E2F6 Transcription Factor
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Epc1 protein, mouse
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Multiprotein Complexes
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Polycomb-Group Proteins
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Proteins
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Repressor Proteins
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TFDP1 protein, human
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Tfdp1 protein, mouse
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Transcription Factor DP1
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Transcription Factors
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EZH2 protein, human
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Enhancer of Zeste Homolog 2 Protein
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Ezh2 protein, mouse
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Histone-Lysine N-Methyltransferase
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Polycomb Repressive Complex 2