CBX8 (D2O8C) Rabbit mAb

The polycomb group (PcG) proteins contribute to the maintenance of cell identity, stem cell self-renewal, cell cycle regulation and oncogenesis by maintaining the silenced state of genes that promote cell lineage specification, cell death and cell-cycle arrest (1-4). PcG proteins exist in two complexes that cooperate to maintain long-term gene silencing through epigenetic chromatin modifications: PRC1 and PRC2. PRC1 is a multi-subunit protein complex consisting of a combination of five core protein families: CBX, RING1, PHC, PCGF, and RYPB (5-7). Different combinations of protein family members lead to a diverse array of PRC1 complexes with distinct functions (8). At least two distinct classes of PRC1 complexes have been defined. The first class, known as canonical PRC1, contains RING1, PHC, PCGF and CBX protein subunits, but not RYPB (5-8). This class of PRC1 complexes requires PRC2 and H3K27Me3 for proper recruitment to target genes. CBX proteins mediate recruitment by binding to H3K27Me3. CBX8 in particular is required for repression of many lineage-specific genes during differentiation of hematopoietic stem cells and may play a role in activation of lineage-specific genes during differentiation of embryonic stem cells (9,10). The second class, known as variant PRC1, contains RYPB instead of CBX proteins (5-8). RYBP-containing PRC1 is recruited to chromatin independently of PRC2 and H3K27Me3. These variant PRC1 complexes can function independently of PRC2, or in some cases function upstream to recruit PRC2 complex to target genes. 1.Boyer, L.A. et al. (2006) Nature 441, 349-53. 2.Lee, T.I. et al. (2006) Cell 125, 301-13. 3.Park, I.K. et al. (2003) Nature 423, 302-5. 4.Molofsky, A.V. et al. (2003) Nature 425, 962-7. 5.Tavares, L. et al. (2012) Cell 148, 664-78. 6.Gao, Z. et al. (2012) Mol Cell 45, 344-56. 7.Blackledge, N.P. et al. (2014) Cell 157, 1445-59. 8.Luis, N.M. et al. (2012) Cell Stem Cell 11, 16-21. 9.Klauke, K. et al. (2013) Nat Cell Biol 15, 353-62. 10.Creppe, C. et al. (2014) PLoS Genet 10, e1004851.