Chromobox protein homolog 8 (CBX8)

Chromobox protein homolog 8 (CBX8) is an epigenetic regulator belonging to the Polycomb group (PcG) and is a core component of Polycomb repressive complex 1 (PRC1)[3][4][6]. CBX8 contains a conserved N-terminal chromodomain that binds methylated histones and contributes to transcriptional repression via chromatin compaction and H2A monoubiquitination, thereby maintaining heritable gene silencing during development and in cancer[6][1][5]. CBX8 is rapidly recruited to sites of DNA damage in a PARP1- and TRIM33-dependent manner, promotes DNA repair via homologous and nonhomologous recombination, and plays a crucial role in the DNA damage response[1][4]. Dysregulation of CBX8 is implicated in multiple cancers (e.g., leukemia, hepatocellular carcinoma, breast cancer), linking its aberrant expression to poor prognosis[3][4][7]. As such, CBX8 is being explored as a potential biomarker and therapeutic target in oncology, although no specific drugs directly targeting CBX8 are currently in clinical use.

Other names

Chromobox 8PC3RC1Polycomb 3 homologRectachrome 1hPc3HPC3polycomb 3Pc class 3 homolog (Drosophila)chromobox homolog 8 (Pc class homolog, Drosophila)

Repression of gene transcription via PRC1-mediated chromatin compaction and H2A ubiquitination. Modulation of DNA repair by recruitment to DNA damage sites. Regulation of key gene loci involved in tumor suppression and cell cycle (e.g., INK4a/ARF, AF9).