CBX1: Chromobox Protein Homolog 1 – Epigenetic Regulator and Heterochromatin Component
Comprehensive gene card for CBX1, including genomic annotations, expression profiles, disease associations, and functional classifications.
Gene Information Card
| Symbol | CBX1 |
|---|---|
| Full Name | Chromobox Protein Homolog 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 17q21.32 |
| NCBI Gene ID | 10951 ncbi.nlm.nih.gov/gene/10951 |
| Ensembl ID | ENSG00000108468 |
| UniProt ID | P83916 |
| OMIM ID | 604511 |
| HGNC ID | 1551 |
| Aliases | HP1-BETA, HP1Hsbeta, M31, MOD1, p25beta |
Description
CBX1 encodes chromobox protein homolog 1, a member of the heterochromatin protein 1 (HP1) family. This protein binds methylated histone H3 lysine 9 (H3K9me) and is essential for heterochromatin formation, gene silencing, and genome stability. CBX1 is involved in transcriptional repression, DNA repair, and cell cycle regulation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Breast cancer | CBX1 overexpression correlates with poor prognosis; promotes proliferation via heterochromatin dysregulation | PMID: 31467438 |
| Prostate cancer | CBX1 upregulation associated with androgen receptor signaling and metastasis | PMID: 29593339 |
| Colorectal cancer | CBX1 silencing reduces tumor growth; acts as an oncogene through chromatin remodeling | PMID: 30606235 |
| Neurodevelopmental disorders | CBX1 mutations linked to intellectual disability and autism spectrum disorder | ClinVar: RCV000626014 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 28.5 | High |
| Bone marrow | 18.2 | Medium |
| Lymph node | 15.7 | Medium |
| Brain cortex | 12.3 | Medium |
| Liver | 8.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 22.4 | Cervical carcinoma; high expression |
| K562 | 19.8 | Leukemia; moderate expression |
| HEK293 | 16.5 | Embryonic kidney; moderate expression |
| MCF7 | 25.1 | Breast cancer; high expression |
| A549 | 14.2 | Lung cancer; moderate expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.337C>T (p.Arg113Trp) | Missense | 0.001% (gnomAD) | Altered H3K9me binding; potential loss of function |
| c.502G>A (p.Gly168Arg) | Missense | 0.0005% (gnomAD) | Reduced heterochromatin localization |
| c.1A>G (p.Met1Val) | Start loss | <0.0001% | Loss of translation initiation; likely null |
Mutation functional classification
Loss of Function (LOF)
Missense variants affecting the chromodomain (e.g., p.Arg113Trp) impair H3K9me binding and heterochromatin formation.
Gain of Function (GOF)
Not well documented; overexpression in cancers suggests possible gain-of-function via increased silencing of tumor suppressors.
Dominant Negative (DN)
Mutations in the chromoshadow domain may disrupt HP1 dimerization, interfering with wild-type CBX1 function.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Chromatin organization (Reactome: R-HSA-4839726)
• Epigenetic regulation of gene expression (KEGG: hsa05202)
• HP1-mediated heterochromatin formation (Reactome: R-HSA-212300)
Protein Summary
CBX1 (HP1 beta) is a 185-amino-acid protein containing an N-terminal chromodomain that recognizes H3K9me3 and a C-terminal chromoshadow domain that mediates dimerization and interaction with other chromatin factors. It localizes to pericentromeric heterochromatin and regulates gene silencing, telomere maintenance, and DNA repair. Post-translational modifications include phosphorylation and sumoylation, which modulate its chromatin association.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CBX1 Knockout HEK293 Cell Line | EDJ-KQ2698 | Human | 10951 | Details Get a Quote |
| CBX1 Knockout A-549 Cell Line | EDJ-KQ23531 | Human | 10951 | Details Get a Quote |
| CBX1 Knockout HCT 116 Cell Line | EDJ-KQ23532 | Human | 10951 | Details Get a Quote |
| CBX1 Knockout HeLa Cell Line | EDJ-KQ23533 | Human | 10951 | Details Get a Quote |
