CCNT2: Cyclin T2
A regulatory subunit of the P-TEFb complex involved in transcriptional elongation and cell cycle control.
Gene Information Card
| Symbol | CCNT2 |
|---|---|
| Full Name | Cyclin T2 |
| Gene Type | Protein coding |
| Chromosomal Location | 2q21.3 |
| NCBI Gene ID | 905 ncbi.nlm.nih.gov/gene/905 |
| Ensembl ID | ENSG00000115947 |
| UniProt ID | O60583 |
| OMIM ID | 603862 |
| HGNC ID | 1600 |
| Aliases | CYCT2, cyclin T2a, cyclin T2b |
Description
CCNT2 encodes cyclin T2, a regulatory subunit of the positive transcription elongation factor b (P-TEFb) complex. P-TEFb, composed of cyclin T2 and CDK9, phosphorylates the C-terminal domain of RNA polymerase II to promote transcriptional elongation. Cyclin T2 is involved in cell cycle regulation, differentiation, and viral replication, particularly HIV-1 Tat-mediated transactivation. Alternative splicing generates isoforms T2a and T2b.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| HIV-1 infection | CCNT2 is a critical cofactor for HIV-1 Tat protein, which recruits P-TEFb to the viral promoter to enhance transcription elongation. | PMID: 10523660 |
| Breast cancer | Overexpression of CCNT2 is associated with poor prognosis and may promote tumor progression by dysregulating transcriptional elongation. | PMID: 25636838 |
| Colorectal cancer | CCNT2 upregulation correlates with increased proliferation and metastasis, potentially via CDK9-mediated transcription of oncogenes. | PMID: 29367608 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 15.2 | Medium |
| Lymph node | 12.8 | Medium |
| Bone marrow | 11.5 | Medium |
| Spleen | 10.9 | Medium |
| Brain | 6.3 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 18.5 | High expression |
| HeLa | 14.2 | High expression |
| K562 | 12.0 | Medium expression |
| MCF7 | 10.1 | Medium expression |
| HepG2 | 8.7 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1123G>A (p.Gly375Arg) | Missense | <0.01% (gnomAD) | Unknown; predicted to affect protein stability |
| c.1456C>T (p.Arg486Trp) | Missense | <0.01% (gnomAD) | Unknown; located in cyclin domain |
| c.1789_1790insA (p.Thr597Asnfs*12) | Frameshift | <0.01% (COSMIC) | Loss of function; truncation of C-terminal region |
Mutation functional classification
Loss of Function (LOF)
Frameshift mutations leading to premature stop codons (e.g., p.Thr597Asnfs*12) are predicted to cause loss of function by disrupting CDK9 binding or P-TEFb complex assembly.
Gain of Function (GOF)
No well-characterized gain-of-function mutations have been reported for CCNT2.
Dominant Negative (DN)
No dominant-negative mutations have been described for CCNT2.
View complete mutation data：
Gene Ontology (GO)
| • protein binding (GO:0005515) | • nucleus (GO:0005634) |
| • regulation of transcription by RNA polymerase II (GO:0006357) | • protein phosphorylation (GO:0006468) |
| • protein kinase binding (GO:0019901) | • positive regulation of transcription elongation from RNA polymerase II promoter (GO:0032781) |
| • positive regulation of transcription by RNA polymerase II (GO:0045944) |
Pathways
• P-TEFb complex (Reactome: R-HSA-167162)
• HIV-1 transcription elongation (Reactome: R-HSA-167243)
• RNA polymerase II transcription elongation (Reactome: R-HSA-75955)
Protein Summary
Cyclin T2 is a 726-amino acid protein (isoform 1) that contains a cyclin N-terminal domain and a C-terminal PEST sequence. It forms a heterodimer with CDK9 to constitute the P-TEFb complex. The cyclin T2/CDK9 complex phosphorylates serine 2 of the RNA polymerase II C-terminal domain, enabling efficient transcriptional elongation. Cyclin T2 also interacts with the HIV-1 Tat protein to facilitate viral transcription. Two major isoforms exist: T2a (full-length) and T2b (lacking exon 7).
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CCNT2 Knockout HEK293 Cell Line | EDJ-KQ3510 | Human | 905 | Details Get a Quote |
| CCNT2 Knockout A-549 Cell Line | EDJ-KQ25323 | Human | 905 | Details Get a Quote |
| CCNT2 Knockout HCT 116 Cell Line | EDJ-KQ25324 | Human | 905 | Details Get a Quote |
| CCNT2 Knockout HeLa Cell Line | EDJ-KQ25325 | Human | 905 | Details Get a Quote |
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