GTF2H5 Gene - General Transcription Factor IIH Subunit 5
Essential component of the TFIIH transcription and DNA repair complex
Gene Information Card
| Symbol | GTF2H5 |
|---|---|
| Full Name | General Transcription Factor IIH Subunit 5 |
| Gene Type | Protein coding |
| Chromosomal Location | 6q25.3 |
| NCBI Gene ID | 404672 ncbi.nlm.nih.gov/gene/404672 |
| Ensembl ID | ENSG00000231852 |
| UniProt ID | Q6ZYL4 |
| OMIM ID | 608780 |
| HGNC ID | 21157 |
| Aliases | TTDA, TFB5, TFIIH basal transcription factor complex TFB5 subunit |
Description
The GTF2H5 gene encodes the 8 kDa TFB5/TTDA subunit of the general transcription factor IIH (TFIIH) complex. TFIIH is a multifunctional complex essential for RNA polymerase II transcription initiation and nucleotide excision repair (NER) of damaged DNA. The TTDA subunit stabilizes the TFIIH complex and is required for efficient NER. Mutations in GTF2H5 cause xeroderma pigmentosum group G (XP-G) with or without Cockayne syndrome features.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Xeroderma Pigmentosum Group G (XP-G) | Defective nucleotide excision repair due to destabilized TFIIH complex | ClinVar, OMIM |
| Cockayne Syndrome (severe form) | Impaired transcription-coupled repair and transcription | OMIM |
| Trichothiodystrophy (photosensitive) | Reduced TFIIH stability affecting both transcription and repair | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 12.5 | Medium |
| Thyroid | 10.2 | Medium |
| Adrenal gland | 9.8 | Medium |
| Lymph node | 8.7 | Medium |
| Brain | 6.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 15.3 | Moderate expression |
| HeLa | 12.1 | Moderate expression |
| K562 | 9.5 | Low expression |
| HepG2 | 8.2 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | Rare | Loss of start codon, likely loss of function |
| c.82C>T (p.Arg28Trp) | Missense | Rare | Reduced TFIIH stability, XP-G phenotype |
| c.164T>C (p.Leu55Pro) | Missense | Rare | Severe XP-G/Cockayne syndrome |
| c.217C>T (p.Arg73*) | Nonsense | Rare | Premature stop, loss of function |
Mutation functional classification
Loss of Function (LOF)
Most reported mutations lead to reduced TFIIH stability and impaired NER, consistent with loss of function.
Gain of Function (GOF)
Not described for GTF2H5.
Dominant Negative (DN)
Not reported; disease inheritance is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • DNA repair (GO:0006281) | • transcription initiation from RNA polymerase II promoter (GO:0006367) |
| • core TFIIH complex (GO:0000439) | • protein binding (GO:0005515) |
Pathways
• hsa03420 - Nucleotide excision repair
• hsa03022 - Basal transcription factors
• hsa05212 - Pancreatic cancer
Protein Summary
The GTF2H5 protein (TTDA) is a small 71-amino acid subunit of the TFIIH complex. It binds to the XPB and XPD helicase subunits and is critical for complex stability. TTDA is not required for basal transcription but is essential for efficient nucleotide excision repair. Its absence or mutation leads to UV sensitivity and defective repair of DNA lesions.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GTF2H5 Knockout HEK293 Cell Line | EDJ-KQ11722 | Human | 404672 | Details Get a Quote |
| GTF2H5 Knockout A-549 Cell Line | EDJ-KQ40079 | Human | 404672 | Details Get a Quote |
| GTF2H5 Knockout HCT 116 Cell Line | EDJ-KQ40080 | Human | 404672 | Details Get a Quote |
| GTF2H5 Knockout HeLa Cell Line | EDJ-KQ40081 | Human | 404672 | Details Get a Quote |
