GTF2B
General Transcription Factor IIB
Gene Information Card
| Symbol | GTF2B |
|---|---|
| Full Name | General Transcription Factor IIB |
| Gene Type | Protein coding |
| Chromosomal Location | 1p22.1 |
| NCBI Gene ID | 2959 ncbi.nlm.nih.gov/gene/2959 |
| Ensembl ID | ENSG00000137942 |
| UniProt ID | Q00403 |
| OMIM ID | 189963 |
| HGNC ID | 4652 |
| Aliases | TFIIB, TF2B, GTF2B |
Description
GTF2B encodes general transcription factor IIB (TFIIB), a key component of the RNA polymerase II pre-initiation complex. TFIIB binds to the core promoter and helps recruit RNA polymerase II and other general transcription factors, facilitating transcription initiation. It also plays a role in promoter selection and transcription start site selection.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Colorectal cancer | Altered expression of GTF2B may affect transcription of growth-related genes; somatic mutations observed in tumors | COSMIC |
| Breast cancer | Overexpression of GTF2B linked to dysregulated transcription; mutations found in cancer genomes | COSMIC |
| Lung cancer | Somatic mutations in GTF2B reported; potential impact on transcription initiation | COSMIC |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 12.5 | Medium |
| Brain | 8.3 | Medium |
| Liver | 6.7 | Low |
| Heart | 5.9 | Low |
| Kidney | 5.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 10.2 | Embryonic kidney cells |
| HeLa | 8.9 | Cervical cancer cells |
| K562 | 7.5 | Leukemia cells |
| HepG2 | 6.8 | Liver cancer cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G | Missense | <0.01% | Alters start codon; potential loss of function |
| c.100C>T | Missense | <0.01% | p.Arg34Cys; may affect DNA binding |
| c.200G>A | Missense | <0.01% | p.Arg67His; reported in COSMIC |
Mutation functional classification
Loss of Function (LOF)
Mutations disrupting DNA binding or protein-protein interactions reduce transcription initiation.
Gain of Function (GOF)
Not well documented; overexpression may enhance transcription of certain genes.
Dominant Negative (DN)
Mutant TFIIB that binds but fails to recruit RNA polymerase II could inhibit transcription.
View complete mutation data：
Gene Ontology (GO)
| • transcription initiation from RNA polymerase II promoter | • DNA-binding transcription factor activity |
| • RNA polymerase II general transcription initiation factor activity | • nucleus |
| • protein binding |
Pathways
• RNA polymerase II transcription initiation
• Formation of the pre-initiation complex
• TFIIB and TFIIF recruitment
Protein Summary
GTF2B encodes TFIIB, a 316-amino acid protein with an N-terminal zinc ribbon domain and a C-terminal core domain. It binds to the TATA box-binding protein (TBP) and RNA polymerase II, stabilizing the pre-initiation complex. TFIIB also interacts with promoter DNA to define the transcription start site.
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