CBX8: Chromobox Protein 8 – Epigenetic Regulator in Development and Cancer
Comprehensive gene card for CBX8, a Polycomb group protein involved in transcriptional repression, stem cell maintenance, and oncogenesis.
Gene Information Card
| Symbol | CBX8 |
|---|---|
| Full Name | Chromobox 8 |
| Gene Type | Protein coding |
| Chromosomal Location | 17q25.3 |
| NCBI Gene ID | 57332 ncbi.nlm.nih.gov/gene/57332 |
| Ensembl ID | ENSG00000141574 |
| UniProt ID | Q9HC52 |
| OMIM ID | 617812 |
| HGNC ID | 15887 |
| Aliases | PC3, RC1, MGC116817 |
Description
CBX8 (Chromobox 8) encodes a component of the Polycomb repressive complex 1 (PRC1). It binds histone H3 trimethylated at lysine 27 (H3K27me3) via its chromodomain and contributes to transcriptional repression of target genes, including those involved in development, differentiation, and cell cycle control. CBX8 is implicated in stem cell maintenance and is frequently dysregulated in various cancers.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Breast cancer | CBX8 overexpression promotes proliferation and invasion via repression of tumor suppressor genes. | PMID: 30523248; COSMIC |
| Colorectal cancer | CBX8 upregulation correlates with poor prognosis and enhances Wnt/β-catenin signaling. | PMID: 29367608; COSMIC |
| Acute myeloid leukemia | CBX8 fusion with NUP98 (NUP98::CBX8) drives leukemogenesis through aberrant transcriptional activation. | PMID: 17634507; COSMIC |
| Hepatocellular carcinoma | CBX8 overexpression promotes cell cycle progression and metastasis. | PMID: 31406129; COSMIC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 12.5 | Medium |
| Bone marrow | 8.2 | Medium |
| Lymph node | 6.7 | Low |
| Brain | 4.3 | Low |
| Liver | 3.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| K562 (leukemia) | 15.8 | High expression |
| HeLa (cervical) | 10.2 | Moderate expression |
| MCF7 (breast) | 9.5 | Moderate expression |
| HepG2 (liver) | 4.1 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| p.Gly34Val | Missense | <0.1% | Unknown functional impact |
| p.Arg106* | Nonsense | <0.1% | Predicted loss of function |
| NUP98::CBX8 fusion | Gene fusion | Rare | Oncogenic; disrupts PRC1 function |
Mutation functional classification
Loss of Function (LOF)
Nonsense mutations (e.g., p.Arg106*) are predicted to truncate the protein, impairing chromodomain-mediated histone binding and PRC1 assembly.
Gain of Function (GOF)
Overexpression in multiple cancers suggests a potential gain-of-function role in promoting proliferation and repressing tumor suppressors.
Dominant Negative (DN)
NUP98::CBX8 fusion may act as a dominant-negative by sequestering PRC1 components and altering target gene expression.
View complete mutation data：
Gene Ontology (GO)
| • chromatin binding (GO:0003682) | • protein binding (GO:0005515) |
| • nucleus (GO:0005634) | • chromatin organization (GO:0006325) |
| • regulation of transcription (GO:0006355) | • chromatin silencing (GO:0006342) |
| • methylated histone binding (GO:0035064) |
Pathways
• Polycomb repressive complex 1 (PRC1) pathway
• Chromatin modifying enzymes
• Transcriptional misregulation in cancer
Protein Summary
CBX8 is a 389-amino-acid protein containing an N-terminal chromodomain that recognizes H3K27me3, a C-terminal Polycomb box (PC box) that mediates interaction with other PRC1 subunits (RING1, BMI1, PHC), and a nuclear localization signal. It functions as a transcriptional repressor by compacting chromatin and ubiquitinating histone H2A at lysine 119. CBX8 is essential for embryonic stem cell self-renewal and lineage commitment. Its dysregulation contributes to oncogenesis in breast, colorectal, liver, and hematopoietic malignancies.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CBX8 Knockout HEK293 Cell Line | EDJ-KQ2256 | Human | 57332 | Details Get a Quote |
| CBX8 Knockout A-549 Cell Line | EDJ-KQ22574 | Human | 57332 | Details Get a Quote |
| CBX8 Knockout HCT 116 Cell Line | EDJ-KQ22575 | Human | 57332 | Details Get a Quote |
| CBX8 Knockout HeLa Cell Line | EDJ-KQ22576 | Human | 57332 | Details Get a Quote |
