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Symbol CCNT1 contributors: mct/npt - updated : 03-04-2016
HGNC name cyclin T1
HGNC id 1599
Location 12q13.12      Physical location : 49.086.751 - 49.110.781
Synonym name
  • subunit of positive elongation transcription factor b
  • CDK9-associated C-type protein
  • cyclin C-related protein
  • human immunodeficiency virus type 1 (HIV-1) expression (elevated) 1
  • Positive Transcriptional Elongation Factor b
  • Synonym symbol(s) CCNT, CYCT1, P-TEFB, HRBL, HIVE1
    TYPE functioning gene
    STRUCTURE 28.54 kb     9 Exon(s)
    10 Kb 5' upstream gene genomic sequence study
    MAPPING cloned Y linked N status provisional
    Physical map
    PFKM 12q13.1 phosphofructokinase, muscle ASB8 12q13.12 ankyrin repeat and SOCS box-containing 8 LOC390311 12 similar to prohibitin LOC387856 12 similar to expressed sequence AI836003 LOC121275 12q13.12 similar to Olfactory receptor 10AD1 LOC341567 12q13.12 HANP1 FLJ31295 12q13.12 hypothetical protein FLJ31295 LOC390312 12 similar to olfactory receptor MOR160-1 ANP32D 12p11.1 acidic (leucine-rich) nuclear phosphoprotein 32 family, member D MGC35033 12q13.12 hypothetical protein MGC35033 LOC341568 12q13.12 similar to seven transmembrane helix receptor LOC390313 12 similar to seven transmembrane helix receptor LALBA 12q13.1 lactalbumin, alpha- LOC121270 12q13.12 similar to olfactory receptor MOR122-1 FLJ20436 12q13.12 hypothetical protein FLJ20436 CCNT1 12q13.1 cyclin T1 LOC255411 12q13.12 hypothetical LOC255411 ADCY6 12q12-q13 adenylate cyclase 6 LOC390314 12 similar to Protein C20orf27 CACNB3 12q13 calcium channel, voltage-dependent, beta 3 subunit DDX23 12q13.12 DEAD (Asp-Glu-Ala-Asp) box polypeptide 23 RHO6 12q12-q13 DEAD (Asp-Glu-Ala-Asp) box polypeptide 23 NYD-SP28 12q13.12 NYD-SP28 protein FKBP11 12q13.2 FK506 binding protein 11, 19 kDa ARF3 12q13.1 ADP-ribosylation factor 3 WNT10B 12q13.1 wingless-type MMTV integration site family, member 10B WNT1 12q13 wingless-type MMTV integration site family, member 1 DDN 12q13.12 dendrin PRKAG1 12q12-q14 protein kinase, AMP-activated, gamma 1 non-catalytic subunit MLL2 12q12-q13 myeloid/lymphoid or mixed-lineage leukemia 2 RHEBL1 12q13.12 Ras homolog enriched in brain like 1 DHH 12q12-q13.1 desert hedgehog homolog (Drosophila) LIMR 12q13.12 lipocalin-interacting membrane receptor K-ALPHA-1 12q12-q14.3 lipocalin-interacting membrane receptor
    TRANSCRIPTS type messenger
    identificationnb exonstypebpproduct
    ProteinkDaAAspecific expressionYearPubmed
    8 - 6915 23 184 - 2013 23569210
  • dE7 and CycT1b
  • detected in several cell lines, including primary human CD4 T cells, and its expression was subject to cell cycle regulation
  • physically interacted with CDK9 and competed with FL CCNT1 for CDK9
  • is a novel splice variant that regulates the expression and function of CCNT1
  • - - 9500 - - peripheral leukocytes 2013 23569210
    - - 3000 - - only in testis 2013 23569210
    9 - 7093 80.7 726 - 2013 23569210
  • CycT1a
    Type restricted
       expressed in (based on citations)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    Respiratoryrespiratory tractlarynx   
    cell lineage
    cell lines
    at STAGE
  • a N terminal cyclin domain, N-terminal AAs are specifically involved in the binding of CCNT1 to HEXIM1 but not to HIV1 Tat
  • a coiled-coil motif
  • a His-rich motif
  • a C terminal PEST sequence
  • mono polymer heteromer , dimer
    interspecies homolog to murine Ccnt1
    homolog to C.elegans F44B9.3
  • cyclin family
  • cyclin C subfamily
  • CATEGORY regulatory , transcription factor
    SUBCELLULAR LOCALIZATION     intracellular
    intracellular,nucleus,nucleoplasm,nuclear bodies,nuclear speckles
    text active form of CCNT1 resides in nuclear speckles and raises the possibility that speckles are sites of CCNT1 function and exchange between negative and positive CCNT1 regulatory complexes
    basic FUNCTION
  • HIV1 expression control
  • playing an active role during lymphoid differentiation through germinal center reaction
  • active role for the CDK9/CCNT1 complex during lymphoid differentiation through germinal center reaction
  • required for RNA polymerase II transcription elongation (Diribarne 2009)
  • functions to induce the elongation step of RNA polymerase II transcription by phosphorylating the carboxyl-terminal domain of the largest subunit of RNA polymerase
  • role for this protein in controlling cell cycle probably via RB/E2F1 pathway
  • CELLULAR PROCESS nucleotide, transcription, elongation
    a component
  • CDK9 (catalytic subunit) and CCNT1 (regulatory subunit) make positive transcription elongation factor B (ptefb)
  • part of CCNT1/HEXIM1/RN7SK complexes (RN7SK is released from CCNT1/HEXIM1/RN7SK complexes upon an arrest in transcription and physiological stimulations such as cardiac hypertrophy, leading to CCNT1 activation)(Diribarne 2009)*
  • super elongation complex (SEC) consists of the POLR2A elongation factors ELL, CCNT1 and several frequent KMT2A translocation partners (PMID;
  • CCNT1 is stored in the 7SK ribonucleoprotein (RNP) that contains the three nuclear proteins HEXIM1, LARP7, and MEPCE
    small molecule
  • RNA polymerase II associated
  • interacting with HIV-1Tat and mediating its high affinity to TAR
  • CDK9
  • associates with HEXIM1 to regulate RNA polymerase II elongation of nascent mRNA transcripts (HEXIM1 recognizes the Cyclin T1 subunit, which is a key step toward the regulation of transcription elongation)
  • BRD4 and HEXIM1 proteins interact with CCNT1 at or very near speckle domain
  • mechanism of release of CCNT1 and HEXIM1 from the RN7SK snRNP by viral and cellular activators includes a conformational change in RN7SK
  • transcription of the HIV-1 requires the interaction of CCNT1 subunit of a host cellular factor, with the viral Tat protein at the transactivation response (TAR) element of nascent viral transcripts
  • mediates the transition from transcription initiation to productive elongation by phosphorylation of the C-terminal domain of RNA polymerase II, and is negatively regulated by the cellular protein HEXIM1
  • CDK9 the kinase of CCNT1 stimulates transcription elongation by phosphorylating POLR2A and transcription elongation factors
  • crucial role for the HEXIM1/CCNT1 pathway in the regulation of satellite cell–mediated muscle regeneration
  • LARP7 suppresses CCNT1 activity to inhibit breast cancer progression and metastasis
  • HEXIM1 binds to the CDK9 catalytic site to inhibit CCNT1
  • TAT promotes the release of CCNT1 from the 7SK RNP through direct binding to the 7SK RNA
  • HEXIM1 in addition to its action on CCNT1, plays a role in a variety of different mechanisms: it controls the stability of transcription factor components and assists binding of transcription factors to their targets
  • MEPCE binds chromatin through the histone H4 tail to serve as a CCNT1 activator at specific genes important for cellular identity
  • cell & other