The dynamic interactome and genomic targets of Polycomb complexes during stem cell differentiation
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ABSTRACT: While the core members of the Polycomb family of proteins (PRC2, PRC1, PR-DUB) are well-characterized, little is known about the specific composition of and protein-protein interactions within these complexes in different cell types. We performed quantitative interaction proteomics and cross-linking mass spectrometry on core Polycomb complex members to identify novel interactors, the relative abundance (stoichiometry) of subunits, and the architecture of these complexes in mouse embryonic stem cells (mESCs) and neural progenitor cells (NPCs). Differentiation to NPCs resulted in dramatic binding changes for several substoichiometric interactors of PRC2 and PRC1. ChIP-seq of core PRC2 and PRC1 subunits in mESCs and NPCs also identified dynamic changes in the genomic localization of these complexes. We observed a loss of PRC2 from most H3K27me3 sites during differentiation, whereas PRC1 is retained at these sites. Additionally, we found PRC1 at enhancers and promoters of active genes independent of PRC2 binding. Overexpression studies using NPC-specific PRC1 interactors demonstrated that the subunit switching observed during differentiation can change PRC1 target site binding. Altogether, these findings extend our understanding of Polycomb family composition, architecture, and genome-wide localization. ChIP-seq samples for Suz12, Ezh2, Ring1b, Pcgf2, and inputs from mouse embryonic stems cells (mES) and neural progenitor cells (NPC) as well as NPC histone H3K4me1 ChIP-seq.
ORGANISM(S): Mus musculus
SUBMITTER: Susan Kloet
PROVIDER: E-GEOD-74330 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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