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Pr55(Gag)
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gag
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CCNT1 isoform b inhibits HIV-1 RT activity in the media and HIV-1 Gag protein expression in the cell lysate in a dose-dependent manner |
PubMed
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gag
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Expression of CycT1 increases Gag production 20-50 fold in rat T cells. Expression of both CRM1 and CycT1 factors synergistically enhances Gag production to levels approximately 10-40% of those detected in human cells |
PubMed
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Tat
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tat
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HIV-1 Tat binds to CDK9 and CCNT1 (CycT1) in an additive manner as shown through Fluoppi (fluorescent-based technology detecting protein-protein interactions) |
PubMed
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tat
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The N-terminus (amino acids 1-48, including activation domain) of HIV-1 Tat binds to P-TEFb through a direct interaction with the N-terminus (amino acids 1-290) of cyclin T1 during Tat-mediated transactivation of the HIV-1 LTR promoter |
PubMed
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tat
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Cyclin T1 mutant N60A fails to bind to HIV-1 Tat and impairs the effect on Tat-mediated transactivation, but H183A mutant exhibits Tat-binding activity and partially disrupts Tat-mediated transactivation |
PubMed
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tat
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PKR-mediated Tat phosphorylation inhibits Tat nuclear localization, and disrupts Tat binding to HIV-1 TAR RNA and interaction with cyclin T1 in HeLa cells |
PubMed
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tat
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A La-related protein, LARP7, is associated with P-TEFb, HEXIM1/2, MEPCE, and 7SK RNA in a large stable complex form. Knockdown of LARP7 decreases the steady-state level of 7SK, but increases free P-TEFb and enhances Tat-mediated transcription |
PubMed
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tat
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Amino acids Q46, Q50 and F176 of human CycT1 protein are involved in its binding to HIV-1 Tat. A triple-mutant containing Q46A, Q50A and F176A mutations in CycT1 completely abolishes the transcriptional activity |
PubMed
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tat
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HIV-1 Tat recruits P-TEFb to the HIV-1 Transcription Activation Response (TAR) RNA during Tat-mediated transactivation of the HIV-1 LTR promoter |
PubMed
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tat
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P-TEFb interacts with HIV-1 Tat as part of both the HIV-1 transcription preinitiation and elongation complexes |
PubMed
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tat
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Cyclin T1 (CCNT1) is identified to interact with HIV-1 Tat mutant Nullbasic in HeLa cells by LC MS/MS |
PubMed
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tat
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A homogeneous assay in AlphaLISA indicates that the affinity between HIV-1 Tat and pTEFb is determined to be approximately 20pM, and only 7% of purified Tat is found to be active in forming tertiary complex with pTEFb |
PubMed
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tat
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Cyclin T1 V107E mutant that exhibits no binding to CDK9 or HEXIM1 has weak interaction with HIV-1 Tat, and inhibits Tat-mediated transactivation in human cells |
PubMed
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tat
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Cyclin T1 N60K mutant that binds weakly with CDK9, but not with HEXIM1 and AFF4, has weak interaction with HIV-1 Tat and inhibits Tat-mediated transactivation in human cells |
PubMed
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tat
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Cyclin T1 Y175E and Y175S mutants exhibit no binding to HEXIM1 and HIV-1 Tat, leading to impair Tat-dependent transactivation of HIV LTR |
PubMed
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tat
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CDK9-CycT1-AFF1 is stimulated by HIV-1 Tat and transferred as a single complex unit to BRD4 upon stress-induced disruption of AFF1-containing 7SK snRNP (HEMX1, MEPCE, LARP7, 7SK RNA, CDK9, CycT1, and AFF1) |
PubMed
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tat
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AFF1 enhances the affinity of HIV-1 Tat for CycT1, which competitively dissociates HEXIM1 and is responsible for AFF1's promotion of Tat's extraction of CDK9/CycT1 from 7SK snRNP |
PubMed
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tat
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Brd4 inhibits HIV-1 Tat-human super elongation complex (components AFF4, ELL2, CycT1, and CDK9) by competing with HIV-1 Tat for binding to P-TEFb on HIV-1 promoter |
PubMed
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tat
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TAR binds Tat and P-TEFb as it emerges on the nascent transcript, competitively displacing the inhibitory 7SK snRNP (HEXIM1 and LARP7) and activating the P-TEFb kinase |
PubMed
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tat
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HIV-1 Tat displaces HEXIM1 from Cyclin T1 in the context of the native 7SK snRNP by interacting with the Cyclin T1-binding domain (amino acid 255-359) of HEXIM1 |
PubMed
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tat
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The interaction of HIV-1 Tat with HIV-1 Transcription Activation Response (TAR) RNA is enhanced by the interaction of Tat with P-TEFb, and TAR RNA also enhances the interaction between Tat and cyclin T1 |
PubMed
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tat
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During HIV-1 Tat mediated transactivation of the HIV-1 LTR promoter, Tat stimulates the phosphorylation of the C-terminal domain (CTD) of RNA polymerase II by P-TEFb, leading to transcription elongation |
PubMed
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tat
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ZASC1, a cellular transcription factor, interacts with HIV-1 Tat and cellular proteins CDK9/Cyclin T1 (P-TEFb) in a TAR-independent manner, suggesting that the Tat/P-TEFb complex in the transcriptional elongation site is promoted by ZASC1 |
PubMed
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tat
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Binding of isolated AFF1(1-308) CBS to CDK9/CycT1 prevents HIV-1 Tat from activating HIV transcription and assembling complete SECs (AFF1, AFF4, ELL2, and ENL). The AFF1(1-308) M60A/L61A mutant shows no suppression of Tat transactivation |
PubMed
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tat
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The crystal structure provides a structural basis for the modulation of TAR RNA binding by acetylation of Lys28 in Tat and for involvement of Asn257 in Cyclin T1 |
PubMed
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tat
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The crystal structure demonstrates that Met55Thr substitution in AFF4 forms a hydrogen bond with Glu246 of Cyclin T1, which is not as favorable for HIV-1 Tat docking |
PubMed
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tat
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The Tat-AFF4-P-TEFb complex containing HIV-1 Tat (residues 1-48), human Cyclin T1 (residues 1-266), human Cdk9 (residues 7-332), and human AFF4 (residues 27-69) is determined by the crystal structure analysis |
PubMed
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tat
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HIV-1 Tat recruits PPM1G phosphatase protein to dephosphorylate the T loop of CDK9 and release P-TEFb from the 7SK snRNP complex |
PubMed
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tat
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The interaction of Tip110 with HIV-1 Tat and the RNAPII C-terminal domain leads to the recruitment of increased CDK9/CycT1 to the transcription complex |
PubMed
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tat
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HIV-1 Tat forms at least two distinct P-TEFb-containing complexes. Tatcom1 is composed of P-TEFb, AF9, ENL, ELL, AFF1, AFF4, and PAF1, presenting strong CTD-kinase activity, while Tatcom2 consists of 7SK, LARP7, and MEPCE with two molecules of Tat/P-TEFb |
PubMed
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tat
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A small molecule compound C3 inhibits HIV-1 replication by suppressing HIV-1 Tat-mediated HIV-1 LTR-driven gene expression and phosphorylation of RNAPII through inhibition of Tat binding to CycT1 |
PubMed
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tat
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Small molecule ligands disrupt the CDK9/Cyclin T1/Tat complex and dissociate CDK9 away from the HIV-1 transcription complex |
PubMed
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tat
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Phosphorylation of CDK9 at position Ser175 regulates the competition between HIV-1 Tat and BRD4 for P-TEFb binding |
PubMed
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tat
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Yeast two-hybrid assay shows that CCNT1 isoform b loss the ability of binding to HIV-1 Tat |
PubMed
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tat
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JQ1, a small molecule inhibitor of Brd4, increases CDK9 T-loop phosphorylation in a Tat-dependent manner and partially dissociates P-TEFb from 7SK snRNP in Jurkat cells |
PubMed
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tat
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CCNT1 that lacks exon 7 inhibits HIV-1 replication through the attenuation of HIV-1 Tat/long terminal repeat (LTR)-driven transcription |
PubMed
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tat
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HIV-1 Tat mutations at positions Y26 and K28 show the most defect in the Tat:TAR:P-TEFb complex formation, but Tat:P-TEFb assembly is not abolished |
PubMed
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tat
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HIV-1 Tat mutations at positions P3, P6, W11, K12, T20, T23, V36, I39, T40, and Y47 show decreased Tat activity and P-TEFb assembly/Cdk9 activation, with three residues P3, P6, and W11 possibly involved in Cdk9 interactions |
PubMed
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tat
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Coexpression of RNA-binding domain deficient Tat (T-RS) and two fusion proteins CycT1N-Rev and Cdk9-Rev synergistically stimulates transcription when P-TEFb is tethered to RNA through Rev, and thus T-RS is no longer an inhibitor |
PubMed
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tat
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An RNA-binding domain deficient Tat excludes wild-type Tat from the promoter by preferentially assembling with P-TEFb through the Tat activation domain, but can not facilitate transfer of P-TEFb to TAR, thus blocking transition to elongation |
PubMed
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tat
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The P-TEFb binding region (amino acids 1209-1362) of BRD4 is required for HIV-1 Tat-mediated release of P-TEFb from the 7SK snRNP |
PubMed
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tat
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HIV-1 Tat-mediated release of P-TEFb from the 7SK sn RNP results in a conformational change in 7SK RNA and release of HEXIM1 from the complex |
PubMed
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tat
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P-TEFb is required for HIV-1 Tat-mediated transcriptional activation |
PubMed
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tat
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HIV-1 Tat stimulates the phosphorylation of SPT5 by P-TEFb during transactivation of the HIV-1 LTR promoter |
PubMed
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tat
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Expression of human cyclin T1 in transgenic mice is sufficient to support HIV-1 Tat-mediated transactivation in primary mouse CD4 T lymphocytes and monocytes/macrophages and increases in vitro and in vivo HIV-1 production |
PubMed
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tat
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HIV-1 Q35L mutant fails to efficiently bind either CDK9 or CycT1 resulting in the defective gene expression. However, the I39Q mutation rescues the Q35L mutant's loss of function |
PubMed
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tat
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Mutant CycT1-U7, which contains four substitutions and one deletion in the N-terminal cyclin box (67HRFYM71 to IIWE), binds HIV-1 Tat to inhibit HIV transcription. The CycT1-U7 protein fails to interact with Cdk9 or HEXIM1 |
PubMed
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tat
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SKIP is required for Tat transactivation in vivo and stimulates HIV-1 transcription elongation by associating with CycT1:CDK9 (P-TEFb) and Tat:P-TEFb complexes both in nuclear extracts and in recombinant Tat:P-TEFb:TAR RNA complexes in vitro |
PubMed
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tat
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HIV-1 Tat and P-TEFb undergo constant association and dissociation cycles with TAR and the elongating polymerase in living cells |
PubMed
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tat
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Mutant CycT1-U7 shows a potent dominant negative effect on Tat-dependent HIV transcription by specifically targeting Tat into the proteasome degradation pathway |
PubMed
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tat
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HIV-1 Tat Lys-28 is required for CycT1-dependent RNA binding. Asn 250, but not Asn-257, in the TRM region of CycT1 is important for unacetylated Tat binding |
PubMed
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tat
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Tat-SF1 is a required cofactor for HIV-1 Tat activity that complexes with P-TEFb and Tat, and stimulates Tat-mediated activation of the HIV-1 LTR promoter |
PubMed
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tat
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Hsp70 and Hsp90/Cdc37 stabilize CDK9 as well as the assembly of an active P-TEFb complex which is stimulated by HIV-1 Tat during HIV-1 transcriptional activation |
PubMed
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tat
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HIV-1 Tat competes with CIITA for the binding to P-TEFb, leading to the downregulation of MHC class II gene expression |
PubMed
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tat
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MAQ1 and 7SK RNA interact with P-TEFb and compete with the binding of HIV-1 Tat to cyclin T1, suggesting the TAR RNA/Tat lentivirus system evolved to subvert the cellular 7SK RNA/MAQ1 system |
PubMed
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tat
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The p160 nuclear receptor co-activator GRIP1 binds to the N-terminal region of HIV-1 Tat, bridging HIV-1 LTR promoter-bound factors to the Tat-P-TEFb complex and enhancing the transactivating activity of Tat |
PubMed
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tat
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The human I-mfa domain-containing protein (HIC) interacts with both P-TEFb and HIV-1 Tat, and modulates Tat transactivation of the HIV-1 LTR promoter |
PubMed
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tat
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Cyclin T1 is capable of recruiting CDK9 and HIV-1 Tat to splicing factor-rich nuclear speckle regions, suggesting nuclear speckles are a site of P-TEFb and Tat function |
PubMed
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tat
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The up and downregulation of expression of CDK9 and cyclin T1 or sequestration of cyclin T1 in infected cells may regulate HIV-1 latency by up or downregulating HIV-1 Tat transcriptional activation |
PubMed
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tat
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Amino acids 260-263 of cyclin T1 are critical for HIV-1 Tat-mediated transcriptional activation, and mediate the species specificity of cyclin T1 and P-TEFb binding to Tat |
PubMed
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tat
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P-TEFb regulates HIV-1 Tat-mediated activation of transcription through two built-in auto inhibitory mechanisms, autophosphorylation of CDK9 and cyclin T1 binding to the transcription elongation factor Tat-SF1 |
PubMed
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tat
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Mutant CycT1 protein containing triple T-to-A mutations in the N-terminal region (amino acids T143, T149, and T155) associates with CDK9 and HIV-1 Tat as a kinase-negative complex and blocks HIV transactivation |
PubMed
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tat
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Undetectable CycT1 protein and un-phosphorylation of CDK9 in undifferentiated monocytes result in the lack of Tat transactivation of the LTR promoter in early viral life cycle |
PubMed
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tat
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The growth factor granulin and the promyelocytic leukemia (PML) protein regulate HIV-1 Tat-mediated transcriptional activation by competing with the Tat interaction with cyclin T1/P-TEFb |
PubMed
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tat
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HIV-1 Tat-mediated stimulation of RNA polymerase II C-terminal domain phosphorylation by P-TEFb leads to stimulation of co-transcriptional capping of HIV-1 mRNA |
PubMed
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tat
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Acetylation of HIV-1 Tat by cellular histone acetyltransferases regulates the binding of Tat to P-TEFb |
PubMed
|
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tat
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Interaction of P-TEFb with histone H1 results in its phosphorylation at position Ser-183 in a Tat-dependent manner, which is necessary for transcription from the HIV-1 LTR |
PubMed
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tat
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PARP1 negatively regulates HIV-1 transcription by directly competing with Tat-P-TEFb complex for binding to TAR RNA |
PubMed
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tat
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PRMT6-mediated arginine methylation of HIV-1 Tat negatively affects Tat-TAR-cyclin T1 ternary complex formation and diminishes cyclin T1-dependent Tat transcriptional activation |
PubMed
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tat
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Cyclin T1-P-TEFb is important for prostratin stimulation of HIV-1 virus expression in the presence of functional Tat |
PubMed
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tat
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IL-10 inhibits HIV-1 gene expression in an HIV-1 Tat-dependent manner by downregulating cyclin T1 expression through the induction of proteasome-mediated proteolysis in human macrophages |
PubMed
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tat
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HIV-1 Tat interaction with cyclin T1 is required for the repression of mannose receptor (MR) and bone morphogenetic protein receptor-2 (BMPR2) promoters |
PubMed
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tat
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P-TEFb, Puralpha and HIV-1 Tat cooperate to activate the TNFalpha promoter |
PubMed
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Vpr
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vpr
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HIV-1 Vpr binds to cyclin T1 (amino acids 300-479) in a ternary complex of HIV-1 Tat, Vpr, Cyclin T1, and CDK9, and enhances Tat transactivation of the viral LTR promoter |
PubMed
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reverse transcriptase
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gag-pol
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CCNT1 isoform b inhibits HIV-1 RT activity in the media and HIV-1 Gag protein expression in the cell lysate in a dose-dependent manner |
PubMed
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