Project description:Polycomb repressive complex PRC1 is essential for gene regulation in numerous cell fate decisions. We show that RING1B (RING2, RNF2) and canonical PRC1 (cPRC1) genes are amplified and overexpressed in breast cancer (BC). Moreover, cPRC1 complexes functionally associate with genes regulated by cell type specific key transcription factors such as estrogen receptor (ER) in ER+ tumor cells and BRD4 in triple negative BC cells. cPRC1 is recruited to active enhancers in a manner independent of PRC2 and RING1B enzymatic activity. RING1B regulates enhancer activity and gene transcription not only by promoting the expression of BC oncogenes but also by regulating chromatin accessibility for oncogenic transcription factors. RING1B recruitment, and thus PRC1 association, to active enhancers occurs in multiple cancers.
Project description:Cohesin and Polycomb proteins functionally interact to control transcription at silenced, restrained, and active genes [expression array data]
Project description:Cohesin and Polycomb proteins functionally interact to control transcription at silenced, restrained, and active genes [tiling array data]
Project description:Cohesin is crucial for proper chromosome segregation, but also regulates gene transcription and organism development by poorly understood mechanisms. We find that in Drosophila, cohesin functionally interacts with Polycomb group (PcG) silencing proteins at both silenced and active genes. Cohesin unexpectedly facilitates binding of Polycomb Repressive Complex 1 (PRC1) to many active genes. In contrast, cohesin and PRC1 binding are mutually antagonistic at silenced genes. PRC1 depletion decreases phosphorylated RNA polymerase and mRNA at many active genes, but increases them at silenced genes. Cohesin also facilitates long-range interactions between Polycomb Response Elements in the invected-engrailed gene complex where it represses transcription. These multiple distinct cohesin-PcG interactions reveal a previously unrecognized role for PRC1 in facilitating productive gene transcription, and provide new insights into how cohesin and PRC1 control development. We extracted RNA from control and Ph RNAi-treated BG3 cells and measured changes in gene expression following Ph dose depletion by hybridization to Affymetrix arrays. We also extracted RNA from wild-type wing imaginal disc and measured control wing disc expression levels by hybridization to Affymetrix arrays.
Project description:Polycomb repressive complex 2-dependent and –independent functions of Jarid2 in transcriptional regulation in Drosophila [Affymetrix]
Project description:Polycomb repressive complex 2-dependent and -independent functions of Jarid2 in transcriptional regulation in Drosophila [ChIP-Seq]
