PRC2 complex

The PRC2 complex (PRC2 stands for: Polycomb Repressive Complex 2) is an important epigenetic regulator that plays a crucial role in genome regulation, particularly in the repression of genes responsible for cell differentiation and other developmental processes. For example, the repressive Polycomb complex 2 silences genes by trimethylating the histone H3K27. PRC2 associates with numerous precursor messenger RNAs (pre-mRNAs) and long non-coding RNAs (lncRNAs) with a binding preference for G-quadruplex RNA (Song J et al. 2023).

The PRC2 complex consists of several protein-containing subunits. The main components include:

- EZH2 (Enhancer of Zeste Homolog 2): The catalytic subunit responsible for the methylation of histone H3 at lysine 27 (H3K27).

- SUZ12: A subunit that is important for the stability of the complex.

- EED (Embryonic ectoderm development): Another subunit involved in the recruitment of EZH2 and in the recognition of already methylated histone H3 (H3K27me3).

Histone methylation: The PRC2 complex is known to methylate histone H3 at lysine 27, resulting in a dense chromatin structure that represses gene expression.

Epigenetic regulation: By methylating histones, the PRC2 complex affects the accessibility of DNA to transcription factors and other regulatory proteins, leading to long-lasting gene repression.

Development: PRC2 plays a crucial role in embryonic development and in maintaining the pluripotent properties of stem cells.

Cell differentiation: The PRC2 complex is critical for the maintenance of stem cell identity and the regulation of differentiation processes by inactivating specific genes.

Cancer: Dysregulation or mutations in the components of the PRC2 complex are associated with various types of cancer, as they can lead to uncontrolled cell proliferation and changes in gene expression.