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FLASH GENE

Symbol

CCNT1

contributors: mct/npt - updated : 03-04-2016

HGNC name	cyclin T1
HGNC id	1599

FLASH GENE DNA RNA EXPRESSION PROTEIN DISORDER ANIMAL & CELL MODELS

RNA

TRANSCRIPTS	type	messenger

identification nb exons type bp product Protein kDa AA specific expression Year Pubmed NM_001277842 8 - 6915 NP_001264771 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 variant 3 - - 9500 isoform 3 - - peripheral leukocytes 2013 23569210 variant 4 - - 3000 isoform 4 - - only in testis 2013 23569210 NM_001240 9 - 7093 NP_001231 80.7 726 - 2013 23569210 CycT1a

EXPRESSION

Type	restricted

expressed in	(based on citations)
organ(s)	System Organ level 1 Organ level 2 Organ level 3 Organ level 4 Level Pubmed Species Stage Rna symbol Lymphoid/Immune spleen         Respiratory respiratory tract larynx       Urinary kidney         Visual eye

cell lineage

cell lines

fluid/secretion

at STAGE

PROTEIN

PHYSICAL PROPERTIES

STRUCTURE

motifs/domains	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

HOMOLOGY

interspecies	homolog to murine Ccnt1
	homolog to C.elegans F44B9.3

Homologene

FAMILY	cyclin family
	cyclin C subfamily

CATEGORY

regulatory , transcription factor

SUBCELLULAR LOCALIZATION	intracellular
	intracellular,nucleus,nucleoplasm,nuclear bodies,nuclear speckles
	intracellular,nucleus,nucleolus
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

PHYSIOLOGICAL PROCESS

PATHWAY

metabolism

signaling

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

INTERACTION

DNA

RNA

small molecule

protein	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

REGULATION

ASSOCIATED DISORDERS

ANIMAL & CELL MODELS