Polycomb group RING finger protein 2, PCGF2, also known as MEL18 or RNF110, is a protein that in humans is encoded by the PCGF2 gene. [5] [6]
The protein encoded by this gene contains a RING finger motif. PCGF2 is a component of the canonical PRC1 complex composed of RING1A/B, CBX2/CBX4, polyhomeotic (PHC) proteins and is very similar to the PCGF4/BMI1 containing PRC1. [7] [8] Canonical PRC1 binds to chromatin via the chromodomain of the CBX subunit that recognizes the H3K27me3 mark deposited by PRC2. [9] [10] Canonical PRC1 complexes have been shown to compact chromatin and mediate higher-order chromatin structures. [11] [12] [13]
Polycomb complexes maintain the transcription repression of genes involved in embryogenesis, cell cycles, and tumorigenesis. PCGF2 was shown to act as a negative regulator of transcription and has tumor suppressor activity. The expression of this gene was detected in various tumor cells, but is limited in neural organs in normal tissues. Knockout studies in mice suggested that this protein may negatively regulate the expression of different cytokines, chemokines, and chemokine receptors, and thus plays an important role in lymphocyte differentiation and migration, as well as in immune responses. [6]
Polycomb-group proteins are a family of protein complexes first discovered in fruit flies that can remodel chromatin such that epigenetic silencing of genes takes place. Polycomb-group proteins are well known for silencing Hox genes through modulation of chromatin structure during embryonic development in fruit flies. They derive their name from the fact that the first sign of a decrease in PcG function is often a homeotic transformation of posterior legs towards anterior legs, which have a characteristic comb-like set of bristles.
Chromobox protein homolog 1 is a protein that in humans is encoded by the CBX1 gene.
Enhancer of zeste homolog 2 (EZH2) is a histone-lysine N-methyltransferase enzyme encoded by EZH2 gene, that participates in histone methylation and, ultimately, transcriptional repression. EZH2 catalyzes the addition of methyl groups to histone H3 at lysine 27, by using the cofactor S-adenosyl-L-methionine. Methylation activity of EZH2 facilitates heterochromatin formation thereby silences gene function. Remodeling of chromosomal heterochromatin by EZH2 is also required during cell mitosis.
Polycomb complex protein BMI-1 also known as polycomb group RING finger protein 4 (PCGF4) or RING finger protein 51 (RNF51) is a protein that in humans is encoded by the BMI1 gene. BMI1 is a polycomb ring finger oncogene.
E3 ubiquitin-protein ligase RING2 is an enzyme that in humans is encoded by the RNF2 gene.
Polycomb protein SUZ12 is a protein that in humans is encoded by the SUZ12 gene.
E3 ubiquitin-protein ligase RING1 is an enzyme that in humans is encoded by the RING1 gene.
Polyhomeotic-like protein 1 is a protein that in humans is encoded by the PHC1 gene.
Polyhomeotic-like protein 2 is a protein that in humans is encoded by the PHC2 gene.
Chromobox protein homolog 5 is a protein that in humans is encoded by the CBX5 gene. It is a highly conserved, non-histone protein part of the heterochromatin family. The protein itself is more commonly called HP1α. Heterochromatin protein-1 (HP1) has an N-terminal domain that acts on methylated lysines residues leading to epigenetic repression. The C-terminal of this protein has a chromo shadow-domain (CSD) that is responsible for homodimerizing, as well as interacting with a variety of chromatin-associated, non-histone proteins.
BRCA1 associated protein-1 is a deubiquitinating enzyme that in humans is encoded by the BAP1 gene. BAP1 encodes an 80.4 kDa nuclear-localizing protein with a ubiquitin carboxy-terminal hydrolase (UCH) domain that gives BAP1 its deubiquitinase activity. Recent studies have shown that BAP1 and its fruit fly homolog, Calypso, are members of the polycomb-group proteins (PcG) of highly conserved transcriptional repressors required for long-term silencing of genes that regulate cell fate determination, stem cell pluripotency, and other developmental processes.
Polycomb group RING finger protein 6 is a protein that in humans is encoded by the PCGF6 gene.
Protein Jumonji is a protein that in humans is encoded by the JARID2 gene. JARID2 is a member of the alpha-ketoglutarate-dependent hydroxylase superfamily.
Chromobox protein homolog 8 is a protein that in humans is encoded by the CBX8 gene.
Chromobox protein homolog 2 is a protein that in humans is encoded by the CBX2 gene. According to a New Scientist article CBX2 controls human sex even more so than X/Y chromosomes.
Polycomb group RING finger protein 1, PCGF1, also known as NSPC1 or RNF68 is a RING finger domain protein that in humans is encoded by the PCGF1 gene.
M33 is a gene. It is a mammalian homologue of Drosophila Polycomb. It localises to euchromatin within interphase nuclei, but it is enriched within the centromeric heterochromatin of metaphase chromosomes. In mice, the official symbol of M33 gene styled Cbx2 and the official name chromobox 2 are maintained by the MGI. Also known as pc; MOD2. In human ortholog CBX2, synonyms CDCA6, M33, SRXY5 from orthology source HGNC. M33 was isolated by means of the structural similarity of its chromodomain. It contains a region of homology shared by Xenopus and Drosophila in the fifth exon. Polycomb genes in Drosophila mediate changes in higher-order chromatin structure to maintain the repressed state of developmentally regulated genes. M33 deficiency interferes with steps upstream of the Y-chromosome-specific SRY gene may cause sex reversal. It may also involved in the campomelic syndrome and neoplastic disorders linked to allele loss in this region. Disruption of the murine M33 gene, displayed posterior transformation of the sternal ribs and vertebral columns.
The human KDM2B gene encodes the protein lysine (K)-specific demethylase 2B.
X chromosome inactivation (XCI) is the phenomenon that has been selected during the evolution to balance X-linked gene dosage between XX females and XY males.
H3K27me3 is an epigenetic modification to the DNA packaging protein Histone H3. It is a mark that indicates the tri-methylation of lysine 27 on histone H3 protein.