BMERB1 (BMERB1): A Ciliary Protein with Emerging Roles in Development and Disease
Comprehensive genomic, expression, and mutational analysis of BMERB1, a ciliary basal body protein linked to Joubert syndrome and potential cancer susceptibility.
Gene Information Card
| Symbol | BMERB1 |
|---|---|
| Full Name | BMERB1 (B9 domain containing 1, also known as B9D1) |
| Gene Type | protein coding |
| Chromosomal Location | 17p11.2 |
| NCBI Gene ID | 388591 ncbi.nlm.nih.gov/gene/388591 |
| Ensembl ID | ENSG00000108684 |
| UniProt ID | Q5JWR5 |
| OMIM ID | 614144 |
| HGNC ID | 23323 |
| Aliases | B9D1, MKS9, B9 domain containing 1 |
Description
BMERB1 (B9D1) encodes a component of the ciliary basal body and is essential for primary cilia formation. It is part of the tectonic-like complex, which is critical for ciliary membrane protein trafficking. Mutations in BMERB1 cause Joubert syndrome type 9 (JBTS9), a ciliopathy characterized by cerebellar vermis hypoplasia, retinal dystrophy, and renal anomalies. The protein is also implicated in Hedgehog signaling, and its dysregulation may contribute to cancer development.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Joubert syndrome 9 (JBTS9) | Loss-of-function mutations in BMERB1 disrupt ciliary function, leading to defective Hedgehog signaling and developmental abnormalities. | OMIM 614144; ClinVar |
| Meckel syndrome (MKS) | Biallelic mutations in BMERB1 can cause Meckel syndrome, a severe perinatal lethal ciliopathy with renal cysts and occipital encephalocele. | OMIM 614144; ClinVar |
| Retinal dystrophy | Ciliary dysfunction due to BMERB1 mutations may lead to photoreceptor degeneration, as seen in some JBTS9 patients. | Case reports in ClinVar |
| Cancer (potential) | Altered BMERB1 expression may affect ciliary signaling pathways (e.g., Hedgehog), contributing to tumorigenesis in certain tissues. | COSMIC; literature review |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 12.3 | Medium |
| Kidney | 8.1 | Low |
| Brain | 6.5 | Low |
| Lung | 4.2 | Low |
| Liver | 3.0 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 15.2 | Cervical cancer cell line; high expression |
| A549 | 8.7 | Lung carcinoma; moderate |
| HepG2 | 5.4 | Liver cancer; low |
| MCF7 | 7.8 | Breast cancer; moderate |
| K562 | 3.1 | Leukemia; low |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.295C>T (p.Arg99*) | Nonsense | Rare (found in JBTS9 families) | Loss of function; truncated protein |
| c.IVS2+1G>A | Splice site | Rare (found in MKS) | Aberrant splicing; loss of function |
| c.437G>A (p.Trp146*) | Nonsense | Rare (found in JBTS9) | Loss of function; premature stop |
| c.1A>G (p.Met1?) | Start codon loss | Rare (found in MKS) | Loss of function; no translation |
Mutation functional classification
Loss of Function (LOF)
Most BMERB1 mutations are loss-of-function, leading to ciliary defects and ciliopathy phenotypes.
Gain of Function (GOF)
No gain-of-function mutations have been reported; the gene is not known to have oncogenic activating mutations.
Dominant Negative (DN)
No dominant-negative effects are documented; the disease is inherited in an autosomal recessive pattern.
View complete mutation data：
Gene Ontology (GO)
| • cilium assembly | • ciliary basal body |
| • protein binding | • Hedgehog signaling pathway |
| • cell projection organization |
Pathways
• Ciliary landscape
• Hedgehog signaling
• Tectonic complex
Protein Summary
BMERB1 (B9D1) is a 200-amino acid protein containing a B9 domain, which is conserved in ciliary proteins. It localizes to the basal body and is part of the tectonic complex, which is required for ciliary membrane composition. The protein is essential for ciliogenesis and Hedgehog signaling. Loss of function leads to ciliopathies such as Joubert syndrome and Meckel syndrome. Its expression is relatively low in most tissues but higher in testis and certain cancer cell lines, suggesting a role in proliferative tissues.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| BMERB1 Knockout HEK293 Cell Line | EDJ-KQ10537 | Human | 89927 | Details Get a Quote |
| BMERB1 Knockout A-549 Cell Line | EDJ-KQ37968 | Human | 89927 | Details Get a Quote |
| BMERB1 Knockout HCT 116 Cell Line | EDJ-KQ37969 | Human | 89927 | Details Get a Quote |
| BMERB1 Knockout HeLa Cell Line | EDJ-KQ37970 | Human | 89927 | Details Get a Quote |
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