GTF3C1 Gene - General Transcription Factor IIIC Subunit 1
Essential component of RNA polymerase III transcription initiation complex
Gene Information Card
| Symbol | GTF3C1 |
|---|---|
| Full Name | General Transcription Factor IIIC Subunit 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 16p12.1 |
| NCBI Gene ID | 2975 ncbi.nlm.nih.gov/gene/2975 |
| Ensembl ID | ENSG00000103544 |
| UniProt ID | Q12789 |
| OMIM ID | 603246 |
| HGNC ID | 4665 |
| Aliases | TFIIIC220, TFIIIC-220, TF3C-220, TFIIICalpha |
Description
GTF3C1 encodes the largest subunit (220 kDa) of the general transcription factor IIIC (TFIIIC) complex. TFIIIC is essential for RNA polymerase III-mediated transcription of small non-coding RNAs, including tRNAs, 5S rRNA, and U6 snRNA. The GTF3C1 subunit directly binds to promoter elements (A and B boxes) and recruits TFIIIB to initiate transcription. It also plays roles in chromatin organization and DNA repair.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Colorectal cancer | Overexpression of GTF3C1 enhances Pol III transcription, promoting tumor growth | PMID: 21502513 |
| Breast cancer | Amplification and overexpression of GTF3C1 linked to poor prognosis | PMID: 25691885 |
| Hepatocellular carcinoma | Upregulation of GTF3C1 correlates with increased tRNA synthesis and proliferation | PMID: 27864381 |
| Intellectual disability | De novo missense variants in GTF3C1 associated with neurodevelopmental phenotypes | ClinVar: RCV001851972 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 18.2 | High |
| Lymph node | 12.5 | Medium |
| Bone marrow | 11.8 | Medium |
| Brain | 8.3 | Medium |
| Liver | 7.1 | Low |
| Heart | 5.6 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 15.4 | Embryonic kidney |
| HeLa | 13.2 | Cervical carcinoma |
| K562 | 11.9 | Leukemia |
| HepG2 | 10.5 | Hepatocellular carcinoma |
| MCF7 | 9.8 | Breast cancer |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.2873G>A (p.Arg958His) | Missense | <0.01% | De novo, associated with intellectual disability |
| c.4010C>T (p.Thr1337Met) | Missense | <0.01% | Reported in ClinVar as uncertain significance |
| c.1234_1235insA (p.Thr412Asnfs*3) | Frameshift | <0.01% | Loss-of-function, rare |
| Amplification (16p12.1) | Copy number gain | ~2% in cancers | Overexpression in breast and colorectal cancer |
Mutation functional classification
Loss of Function (LOF)
Frameshift and nonsense variants predicted to cause haploinsufficiency; associated with neurodevelopmental phenotypes.
Gain of Function (GOF)
Gene amplification and overexpression in cancers lead to increased Pol III transcription and oncogenic growth.
Dominant Negative (DN)
Not well characterized; missense variants may interfere with TFIIIC complex assembly.
View complete mutation data：
Gene Ontology (GO)
Pathways
• RNA polymerase III transcription initiation (R-HSA-76061)
• TFIIIC complex assembly (R-HSA-76066)
• Gene expression (R-HSA-74160)
Protein Summary
GTF3C1 (TFIIIC220) is a 2109-amino acid protein containing multiple domains: an N-terminal region for TFIIIB recruitment, a central DNA-binding domain recognizing the B-box promoter element, and a C-terminal region involved in complex stability. It is post-translationally modified by phosphorylation and acetylation, which regulate its activity and interaction with chromatin.
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