GSE159747
Elucidation of the BMI1 interactome identifies novel regulatory roles in glioblastoma
Glioblastoma (GBM) is the most common and aggressive intrinsic brain tumour in adults. Epigenetic mechanisms controlling normal brain development are often dysregulated in GBM. Among these, BMI1, a structural component of the Polycomb Repressive Complex 1 (PRC1), which promotes the H2AK119ub catalytic activity of Ring1B, is upregulated in GBM and its tumorigenic role has been shown in vitro and in vivo. Here, we have used protein and chromatin immunoprecipitation followed by mass spectrometry (MS) analysis to elucidate the protein composition of PRC1 in GBM and CRISPR/dCAS9-mediated modulation of BMI1 to assess its influence on protein interactions. We show that while well-established BMI1 functions such as control of cell proliferation and cell adhesion are PRC1-dependent, novel regulatory functions in mRNA splicing and cholesterol transport are PRC1 independent and may represent novel targetable mechanisms in GBM. Overall design: Proteome analysis to elucidate BMI1 specific interactome and RNA-Seq of BMI1 and selected candidates RYBP, CBX8 and PRP6 to underpin specific biological functions and RNA splicing modulation.