CCNT1
Cyclin T1, a regulatory subunit of the P-TEFb complex essential for transcriptional elongation
Gene Information Card
| Symbol | CCNT1 |
|---|---|
| Full Name | Cyclin T1 |
| Gene Type | Protein coding |
| Chromosomal Location | 12q13.11 |
| NCBI Gene ID | 904 ncbi.nlm.nih.gov/gene/904 |
| Ensembl ID | ENSG00000122884 |
| UniProt ID | O60563 |
| OMIM ID | 143055 |
| HGNC ID | 1599 |
| Aliases | CYCT1, HIVE1 |
Description
CCNT1 encodes cyclin T1, a regulatory subunit of the positive transcription elongation factor b (P-TEFb). P-TEFb, composed of cyclin T1 and CDK9, phosphorylates RNA polymerase II and negative elongation factors to promote transcriptional elongation. CCNT1 is essential for normal gene expression and is hijacked by HIV-1 Tat to enhance viral transcription. Dysregulation of CCNT1 is implicated in cancer and other diseases.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| HIV-1 infection | HIV-1 Tat protein recruits P-TEFb via cyclin T1 to activate viral transcription | PMID: 9428514 |
| Breast cancer | Overexpression of CCNT1 promotes cell proliferation and tumor growth | PMID: 23555264 |
| Colorectal cancer | CCNT1 amplification correlates with poor prognosis | PMID: 29255176 |
| Acute myeloid leukemia | CCNT1 fusion with MLL gene drives leukemogenesis | PMID: 12629597 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Bone marrow | 18.2 | Medium |
| Lymph node | 15.7 | Medium |
| Testis | 12.3 | Medium |
| Brain | 8.5 | Low |
| Liver | 6.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 22.4 | High expression |
| HeLa | 19.8 | High expression |
| K562 | 16.5 | Medium expression |
| MCF7 | 14.2 | Medium expression |
| HepG2 | 9.3 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1234C>T | Missense | 0.01% | p.Pro412Ser; unknown functional impact |
| c.789_790insA | Frameshift | 0.005% | Predicted loss of function |
| c.1567G>A | Synonymous | 0.02% | No amino acid change |
Mutation functional classification
Loss of Function (LOF)
Frameshift and nonsense mutations that truncate the cyclin domain are predicted to impair P-TEFb assembly and transcriptional elongation.
Gain of Function (GOF)
Amplification or overexpression of CCNT1 is observed in cancers, leading to increased P-TEFb activity and oncogenic transcription.
Dominant Negative (DN)
Mutations that disrupt CDK9 binding but retain Tat interaction may act as dominant negatives in HIV-1 replication.
View complete mutation data：
Gene Ontology (GO)
Pathways
• P-TEFb elongation complex (Reactome: R-HSA-112382)
• HIV-1 transcription elongation (Reactome: R-HSA-167243)
• Transcriptional regulation by the AP-2 family (Reactome: R-HSA-8866907)
Protein Summary
Cyclin T1 is a 726-amino acid protein containing a cyclin box domain that mediates interaction with CDK9. It forms the P-TEFb complex, which phosphorylates Ser2 of RNA polymerase II CTD and negative elongation factors (NELF, DSIF) to release paused polymerase. Cyclin T1 also binds the HIV-1 Tat protein, a critical step for viral transcription. The protein is ubiquitously expressed with higher levels in hematopoietic tissues.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CCNT1 Knockout HEK293 Cell Line | EDJ-KQ2254 | Human | 904 | Details Get a Quote |
| CCNT1 Knockout A-549 Cell Line | EDJ-KQ22568 | Human | 904 | Details Get a Quote |
| CCNT1 Knockout HCT 116 Cell Line | EDJ-KQ22569 | Human | 904 | Details Get a Quote |
| CCNT1 Knockout HeLa Cell Line | EDJ-KQ22570 | Human | 904 | Details Get a Quote |
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