# CCNT1

Source: https://onco.cc/targets/ccnt1/  
OnCo record `ccnt1` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

CCNT1 (Cyclin-T1) is a protein that switches other genes on and off. In the public catalogues it is called a cancer driver by mutation analysis of patient cohorts. Tied to Acute myeloid leukaemia.

## Summary

Regulatory subunit of the cyclin-dependent kinase pair (CDK9/cyclin-T1) complex, also called positive transcription elongation factor B (P-TEFb), which facilitates the transition from abortive to productive elongation by phosphorylating the CTD (C-terminal domain) of the large subunit of RNA polymerase II (RNA Pol II). Required to activate the protein kinase activity of CDK9: acts by mediating formation of liquid-liquid phase separation (LLPS) that enhances binding of P-TEFb to the CTD of RNA Pol II. Serves as an essential cofactor for Tat, by promoting RNA Pol II activation, allowing transcription of viral genes.

IntOGen calls it a driver in 1 cohort (0 activating, 0 loss-of-function), covering Acute Myeloid Leukaemia.

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: cyclin T1; Cyclin-T1; CYCT1; HIVE1
- Tags: cancer-genes-wave
- Symbol: CCNT1
- Class: transcription
- Biology: Regulatory subunit of the cyclin-dependent kinase pair (CDK9/cyclin-T1) complex, also called positive transcription elongation factor B (P-TEFb), which facilitates the transition from abortive to productive elongation by phosphorylating the CTD (C-terminal domain) of the large subunit of RNA polymerase II (RNA Pol II). Required to activate the protein kinase activity of CDK9: acts by mediating formation of liquid-liquid phase separation (LLPS) that enhances binding of P-TEFb to the CTD of RNA Pol II. Serves as an essential cofactor for Tat, by promoting RNA Pol II activation, allowing transcription of viral genes. Location: Nucleus (UniProt). Locus 12q13.11-q13.12 (HGNC).
- Where found: Acute myeloid leukaemia: IntOGen driver in 1 cohort (AML)

## Notes

- Written by scripts/fetch-cancer-genes.ts from CIViC, Open Targets, IntOGen, HGNC and UniProt; the function text is UniProt's, condensed and in UK spelling. Roles: none stated by the sources. Evidence tier "cohort-driver" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:1599: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:1599
- UniProt O60563: https://www.uniprot.org/uniprotkb/O60563/entry
- NCBI Gene 904: https://www.ncbi.nlm.nih.gov/gene/904
- Ensembl ENSG00000129315: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000129315

## Connected records

- collections: [IntOGen](https://onco.cc/collections/intogen/)
- cancers: [Acute myeloid leukaemia](https://onco.cc/cancers/aml/)

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JSON: https://onco.cc/api/v1/entities/ccnt1.json