Project description:Gene regulatory networks are pivotal for many biological processes. In mouse embryonic stem cells (mESCs), the transcriptional network can be divided into three functionally distinct modules: Polycomb, Core, and Myc. The Polycomb module represses developmental genes, while the Myc module is associated with proliferative functions, and its mis-regulation is linked to cancer development. Here, we show that, in mESCs, the Polycomb repressive complex 2 (PRC2)-associated protein EPOP (Elongin BC and Polycomb Repressive Complex 2-associated protein; a.k.a. C17orf96, esPRC2p48, and E130012A19Rik) co-localizes at chromatin with members of the Myc and Polycomb module. EPOP interacts with the transcription elongation factor Elongin BC and the H2B deubiquitinase USP7 to modulate transcriptional processes in mESCs similar to MYC. EPOP is commonly upregulated in human cancer, and its loss impairs the proliferation of several human cancer cell lines. Our findings establish EPOP as a transcriptional modulator, which impacts both Polycomb and active gene transcription in mammalian cells.
Project description:Gene regulatory networks are pivotal for many biological processes. In mouse embryonic stem cells (mESCs) the transcriptional network can be divided into three functionally distinct modules: Polycomb, Core and Myc. The Polycomb module represses developmental genes, while the Myc module is associated with proliferative functions and its mis-regulation is linked to cancer development. Here, we show that in mESCs the Polycomb Repressive Complex 2 (PRC2) associated protein EPOP (a.k.a C17orf96, esPRC2p48, E130012A19Rik) co-localizes at chromatin with members of the Myc and Polycomb module. EPOP interacts with the transcription elongation factor Elongin BC and the H2B deubiquitinase USP7 to modulate transcriptional processes in mESCs similar to MYC. EPOP is commonly up-regulated in human cancer and we demonstrate that its loss impairs the proliferation of several human cancer cell lines. Our findings establish EPOP as a unique modulator of transcriptional processes, impacting both Polycomb and active gene transcription in mammalian cells.
Project description:Gene regulatory networks are pivotal for many biological processes. In mouse embryonic stem cells (mESCs) the transcriptional network can be divided into three functionally distinct modules: Polycomb, Core and Myc. The Polycomb module represses developmental genes, while the Myc module is associated with proliferative functions and its mis-regulation is linked to cancer development. Here, we show that in mESCs the Polycomb Repressive Complex 2 (PRC2) associated protein EPOP (a.k.a C17orf96, esPRC2p48, E130012A19Rik) co-localizes at chromatin with members of the Myc and Polycomb module. EPOP interacts with the transcription elongation factor Elongin BC and the H2B deubiquitinase USP7 to modulate transcriptional processes in mESCs similar to MYC. EPOP is commonly up-regulated in human cancer and we demonstrate that its loss impairs the proliferation of several human cancer cell lines. Our findings establish EPOP as a unique modulator of transcriptional processes, impacting both Polycomb and active gene transcription in mammalian cells.
Project description:Gene regulatory networks are pivotal for many biological processes. In mouse embryonic stem cells (mESCs) the transcriptional network can be divided into three functionally distinct modules: Polycomb, Core and Myc. The Polycomb module represses developmental genes, while the Myc module is associated with proliferative functions and its mis-regulation is linked to cancer development. Here, we show that in mESCs the Polycomb Repressive Complex 2 (PRC2) associated protein EPOP (a.k.a C17orf96, esPRC2p48, E130012A19Rik) co-localizes at chromatin with members of the Myc and Polycomb module. EPOP interacts with the transcription elongation factor Elongin BC and the H2B deubiquitinase USP7 to modulate transcriptional processes in mESCs similar to MYC. EPOP is commonly up-regulated in human cancer and we demonstrate that its loss impairs the proliferation of several human cancer cell lines. Our findings establish EPOP as a unique modulator of transcriptional processes, impacting both Polycomb and active gene transcription in mammalian cells.
Project description:The cellular plasticity of pluripotent stem cells is thought to be sustained by genomic regions that display both active and repressive chromatin properties. These regions exhibit low levels of gene expression, yet the mechanisms controlling these levels remain unknown. Here, we describe Elongin BC as a binding factor at the promoters of bivalent sites. Biochemical and genome-wide analysis shows that Elongin BC is associated with Polycomb Repressive Complex 2 (PRC2) in pluripotent stem cells. Elongin BC is recruited to chromatin by the PRC2-associated factor EPOP (Elongin- and POlycomb-associated Protein, also termed C17orf96, esPRC2p48, E130012A19Rik), a protein expressed in the inner cell mass of the mouse blastocyst. Both EPOP and Elongin BC are required to maintain low levels of expression at PRC2 genomic targets. Our results indicate that keeping the balance between activating and repressive cues is a more general feature of chromatin in pluripotent stem cells than previously appreciated.
Project description:The Elongin BC complex was identified initially as a positive regulator of RNA polymerase II (Pol II) elongation factor Elongin A and subsequently as a component of the multiprotein von Hippel-Lindau (VHL) tumor suppressor complex, in which it participates in both tumor suppression and negative regulation of hypoxia-inducible genes. Elongin B is a ubiquitin-like protein, and Elongin C is a Skp1-like protein that binds to a BC-box motif that is present in both Elongin A and VHL and is distinct from the conserved F-box motif recognized by Skp1. In this report, we demonstrate that the Elongin BC complex also binds to a functional BC box present in the SOCS box, a sequence motif identified recently in the suppressor of cytokine signaling-1 (SOCS-1) protein, as well as in a collection of additional proteins belonging to the SOCS, ras, WD-40 repeat, SPRY domain, and ankyrin repeat families. In addition, we present evidence (1) that the Elongin BC complex is a component of a multiprotein SOCS-1 complex that attenuates Jak/STAT signaling by binding to Jak2 and inhibiting Jak2 kinase, and (2) that by interacting with the SOCS box, the Elongin BC complex can increase expression of the SOCS-1 protein by inhibiting its degradation. These results suggest that Elongin BC is a multifunctional regulatory complex capable of controlling multiple pathways in the cell through interaction with a short degenerate sequence motif found in many different proteins.