Table 1 PcG proteins core complex components in D. melanogaster and human
From: Epigenetic regulation of HIV-1 latency: focus on polycomb group (PcG) proteins
PcG subunits in Drosophila melanogaster | PcG subunits in humans | Protein domains | Biochemical functions |
|---|---|---|---|
Polycomb-repressive complex 1 (PRC1) | |||
 Polyhomeotic proximal (PH-P) and distal (PH-D) | PHC-1/EDR1, PHC-2/EDR2, PHC-3/EDR3 | C2-C2 zinc-finger and SAM Domain | Higher order interaction? |
 Posterior sex comb (PSC)/suppressor 2 of Zeste (Su(z)2) | BMI1/PCGF4 MEL18/PCGF2 NSPC1/PCGF1 RNF110/ZFP144 | Ring finger domain (C3HC4 Zinc-finger) | Co-factor for SCE and compacts chromatin |
 Polycomb (PC) | CBX2/HPC1 CBX4/HPC2 CBX6, CBX7 and CBX8/HPC3 | Shadow domain and chromodomain | Binds to H3K27 trimethylation marks and CBX4 is reported to be a SUMO E3-ligase |
 Sex comb extra (SCE)/dRING | RING1/RING1A, RNF1 RING2/RING1B, RNF2 | Ring-finger domain (C3HC4 Zinc-finger) | Ubiquitinates H2AK118 (H2AK119 in vertebrates) and compacts the chromatin |
 Sex comb on midleg (SCM) | SCMH1 SCML2 | MBTs, SAM, DUF3588 and Zinc-finger and SPM domain | ? |
Polycomb-repressive complex 2 (PRC2) | |||
 Enhancer of Zeste (E(z)) | EZH1 and EZH2/KMT6 | CXC domain, SET domain, SANT and homolog domain I and II | Catalyzes trimethylation (H3K27) |
 Suppressor of Zeste 12 (Su(z)12) | SUZ12 | C2-H2 Zinc-finger, VEFS Box, alanine rich and Glycine rich | Enhances the enzymatic activities of EZ and also important for nucleosome binding |
 Extra sex comb (ESC) | EED or WAIT-1 | WD-40 repeats | Stimulates H3K27 methyltransferase |
 Extra sex comb like (ESCL) | |||
 Chromatin assembly factor 1 (Caf1)/nucleosome remodeling factor 55 (Nurf55) | RbAp46/RBBP7 RbAp48/RBBP4 | WD-40 repeats | Binds to histones and suppressor of Zeste 12 |
 Polycomb-like (PCL) | PHF1/PCL1 MTF2/PCL2 PHF19/PCL3 | PHD finger and tudor domain | Induces trimethylations and recruits PRC2 |
Pleiohomeotic (Pho)-repressive complex (Pho-RC) | |||
 PHO | YY1, YY2 | Zinc-finger | DNA binding |
 SFMBT (CG16975) |  | MBT and SAM | Bind to mono- and dimethylated histone at H3K9 and H4K20 |