SNRPB: Small Nuclear Ribonucleoprotein Polypeptides B and B1
A core component of the spliceosome, essential for pre-mRNA splicing and linked to developmental disorders and cancer.
Gene Information Card
| Symbol | SNRPB |
|---|---|
| Full Name | Small Nuclear Ribonucleoprotein Polypeptides B and B1 |
| Gene Type | Protein coding |
| Chromosomal Location | 20p13 |
| NCBI Gene ID | 6628 ncbi.nlm.nih.gov/gene/6628 |
| Ensembl ID | ENSG00000125870 |
| UniProt ID | P14678 |
| OMIM ID | 182282 |
| HGNC ID | 11153 |
| Aliases | Sm-B/B', SmB, SmB1, snRNP-B, B/B' |
Description
SNRPB encodes the B and B' proteins, core components of the Sm core domain of small nuclear ribonucleoproteins (snRNPs). These snRNPs are essential for the assembly of the spliceosome, the complex responsible for pre-mRNA splicing. SNRPB is also involved in the SMN (survival of motor neuron) complex assembly pathway. Mutations in SNRPB cause Cerebrocostomandibular syndrome (CCMS) and are implicated in various cancers.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Cerebrocostomandibular syndrome (CCMS) | Loss-of-function mutations in SNRPB disrupt snRNP assembly and pre-mRNA splicing, leading to developmental defects in the brain, ribs, and jaw. | OMIM #117650; ClinVar |
| Breast cancer | Overexpression and somatic mutations in SNRPB are associated with altered splicing patterns that promote tumorigenesis. | COSMIC; NCBI PubMed |
| Lung cancer | SNRPB amplification and increased expression correlate with poor prognosis and aberrant splicing of oncogenes. | COSMIC; NCBI PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | High |
| Heart | 10.2 | Medium |
| Liver | 8.7 | Medium |
| Lung | 9.1 | Medium |
| Testis | 15.3 | High |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 14.0 | High expression; used in spliceosome studies |
| HEK293 | 11.5 | Medium expression; common model |
| A549 | 10.8 | Medium expression; lung cancer cell line |
| MCF7 | 13.2 | High expression; breast cancer cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.164G>A (p.Arg55Gln) | Missense | <0.01% | Reduces Sm protein binding; associated with CCMS |
| c.1A>G (p.Met1Val) | Start loss | <0.01% | Loss of translation initiation; CCMS |
| c.502C>T (p.Arg168*) | Nonsense | <0.01% | Premature stop; loss of function; CCMS |
| Amplification | Copy number gain | 1-2% in lung cancer | Overexpression; oncogenic potential |
Mutation functional classification
Loss of Function (LOF)
Nonsense, frameshift, and start-loss mutations in SNRPB lead to haploinsufficiency, causing Cerebrocostomandibular syndrome.
Gain of Function (GOF)
Amplification and overexpression in cancers may confer a gain-of-function by enhancing splicing of pro-proliferative transcripts.
Dominant Negative (DN)
Missense mutations (e.g., p.Arg55Gln) can disrupt snRNP assembly, potentially acting in a dominant-negative manner by sequestering other Sm proteins.
View complete mutation data：
Gene Ontology (GO)
| • mRNA splicing (GO:0000398) | • spliceosomal complex (GO:0005681) |
| • spliceosomal snRNP assembly (GO:0000245) | • small nuclear ribonucleoprotein complex (GO:0030532) |
| • RNA binding (GO:0003723) |
Pathways
• hsa03040: Spliceosome
• hsa05022: Pathways of neurodegeneration - multiple diseases
• R-HSA-72163: mRNA Splicing - Major Pathway
Protein Summary
The SNRPB protein (Sm-B/B') is a 240-amino-acid core component of the Sm ring in U1, U2, U4/U6, and U5 snRNPs. It contains a conserved Sm domain that mediates RNA binding and protein-protein interactions. The protein is essential for spliceosome assembly and pre-mRNA splicing. Alternative splicing of SNRPB itself produces two isoforms, B and B', which differ by 11 amino acids.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SNRPB2 Knockout HEK293 Cell Line | EDJ-KQ15408 | Human | 6629 | Details Get a Quote |
| SNRPB2 Knockout A-549 Cell Line | EDJ-KQ46182 | Human | 6629 | Details Get a Quote |
| SNRPB2 Knockout HCT 116 Cell Line | EDJ-KQ46183 | Human | 6629 | Details Get a Quote |
| SNRPB2 Knockout HeLa Cell Line | EDJ-KQ44932 | Human | 6629 | Details Get a Quote |
