Polycomb silencing is an essential epigenetic mechanism that plays a key role in chromatin remodelling and gene regulation. In essence it involves the recruitment of Polycomb group (PcG) proteins to specific genomic loci to maintain genes in a gene silenced state. Polycomb gene silencing is characterized by the deposition of specific repressive histone marks on chromatin, primarily H3K27me3 (trimethylation of histone H3 at lysine 27). PcG proteins, such as PRC2 (Polycomb Repressive Complex 2), catalyse the addition of the key methyl groups to histone H3 at lysine 27. This mark is then recognized by other PcG proteins and helps maintain a condensed chromatin structure that is transcriptionally silent. Polycomb silencing involves the assembly of multi-protein complexes, known as Polycomb Repressive Complexes (PRCs), that work together to repress gene expression. PRCs consist of various PcG proteins, including core components like EZH2 (Enhancer of Zeste Homolog 2), which has methyltransferase activity for H3K27me3, and additional factors such as Embryonic Ectoderm Development (EED) and Suppressor of Zeste 12 (SUZ12). These complexes interact with each other to form different PRC variants, each with specific functions in gene repression. Polycomb silencing plays a fundamental role in regulating gene expression during developmental processes, ensuring that specific genes are repressed in particular cell types or developmental stages. PcG proteins are therefore recruited to genes that need to be repressed during development. They maintain a repressive chromatin state at these genes, preventing their premature activation. As cells differentiate, PcG-mediated repression is lifted at certain loci, allowing for appropriate gene expression changes. In some cases, genes that are poised for activation during development possess both activating and repressive histone marks, creating a bivalent chromatin state. Bivalently marked genes have H3K4me3 (trimethylation of histone H3 at lysine 4), an activating mark, along with H3K27me3, a repressive mark. PcG proteins are responsible for maintaining the H3K27me3 mark, whilst other factors establish H3K4me3. This dual marking allows genes to be quickly activated or repressed in response to different developmental cues. Overall, Polycomb silencing contributes to the maintenance of cellular identity by repressing genes associated with alternative cell fates, ensuring that cells maintain their specific identity by repressing genes that are characteristic of other cell types. This repression is essential for the stable maintenance of cell fate and function. Polycomb silencing additionally provides epigenetic memory by stably maintaining gene repression through repeated cell divisions and across generations. PcG proteins therefore ensure that repressive histone marks are faithfully inherited during DNA replication. This epigenetic memory allows cells to maintain the silenced state of inappropriate genes over time. Dysregulation of Polycomb silencing is associated with various diseases, including cancer. For example, SUZ12 is a core component of the Polycomb Repressive Complex 2 (PRC2) and mutations in SUZ12 have been identified in endometrial cancers, resulting in the loss of PRC2 function. This leads to the de-repression of genes involved in cell proliferation and differentiation, contributing to tumorigenesis. We provide a wide product range of research reagents for investigating polycomb silencing, including Bmi1 antibodies, ASF1A antibodies, PIM1 antibodies, EZH1 antibodies, and WDR77 antibodies. Explore our full polycomb silencing product range below and discover more, for less. Alternatively, you can explore our PRC2, PRC3, and PRC1 product ranges.