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  1. Article ; Online: Hexim1, an RNA-controlled protein hub.

    Michels, Annemieke A / Bensaude, Olivier

    Transcription

    2018  Volume 9, Issue 4, Page(s) 262–271

    Abstract: Hexim1 acts as a tumor suppressor and is involved in the regulation of innate immunity. It was initially described as a non-coding RNA-dependent regulator of transcription. Here, we detail how 7SK RNA binds to Hexim1 and turns it into an inhibitor of the ...

    Abstract Hexim1 acts as a tumor suppressor and is involved in the regulation of innate immunity. It was initially described as a non-coding RNA-dependent regulator of transcription. Here, we detail how 7SK RNA binds to Hexim1 and turns it into an inhibitor of the positive transcription elongation factor (P-TEFb). In addition to its action on P-TEFb, it 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.
    MeSH term(s) Humans ; Immunity, Innate ; RNA, Long Noncoding/genetics ; RNA, Long Noncoding/metabolism ; RNA-Binding Proteins/immunology ; RNA-Binding Proteins/metabolism ; Transcription, Genetic/drug effects ; Transcription, Genetic/genetics
    Chemical Substances HEXIM1 protein, human ; RNA, Long Noncoding ; RNA-Binding Proteins ; long non-coding RNA 7SK, human
    Language English
    Publishing date 2018-02-23
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 2646974-1
    ISSN 2154-1272 ; 2154-1264
    ISSN (online) 2154-1272
    ISSN 2154-1264
    DOI 10.1080/21541264.2018.1429836
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: MAF1: a new target of mTORC1.

    Michels, Annemieke A

    Biochemical Society transactions

    2011  Volume 39, Issue 2, Page(s) 487–491

    Abstract: Yeast and mammalian MAF1 are both regulated by the TOR (target of rapamycin) pathway. However, the exact mechanisms of regulation diverge at TOR, with yeast Maf1 phosphorylated mainly by the TORC1 (TOR complex 1) substrate Sch9 kinase and mammalian MAF1 ... ...

    Abstract Yeast and mammalian MAF1 are both regulated by the TOR (target of rapamycin) pathway. However, the exact mechanisms of regulation diverge at TOR, with yeast Maf1 phosphorylated mainly by the TORC1 (TOR complex 1) substrate Sch9 kinase and mammalian MAF1 by mTORC1 (mammalian target of rapamycin complex 1) itself. Sch9 phosphorylation of yeast Maf1 regulates Maf1 localization, but it is less clear whether phosphorylation of human MAF1 regulates its localization. Replacement of phosphosites with alanine decreases Pol III (RNA polymerase III) transcription, but the effect is much more pronounced for human MAF1 than for the yeast protein. In both cases, Pol III repression can be further increased by rapamycin treatment or, in mammalian cells, serum starvation, suggesting that the TOR pathway controls another aspect of Pol III transcription that is closely linked to MAF1, as it depends on the presence of MAF1.
    MeSH term(s) Animals ; Catalytic Domain ; Humans ; Mechanistic Target of Rapamycin Complex 1 ; Models, Biological ; Multiprotein Complexes ; Phosphorylation ; Protein Transport ; Protein-Serine-Threonine Kinases/metabolism ; Protein-Serine-Threonine Kinases/physiology ; Proteins/metabolism ; Proteins/physiology ; Repressor Proteins/chemistry ; Repressor Proteins/metabolism ; Repressor Proteins/physiology ; Saccharomyces cerevisiae Proteins/metabolism ; Saccharomyces cerevisiae Proteins/physiology ; TOR Serine-Threonine Kinases ; Yeasts/genetics ; Yeasts/metabolism
    Chemical Substances MAF1 protein, human ; Multiprotein Complexes ; Proteins ; Repressor Proteins ; Saccharomyces cerevisiae Proteins ; TOR Serine-Threonine Kinases (EC 2.7.1.1) ; Mechanistic Target of Rapamycin Complex 1 (EC 2.7.11.1) ; Protein-Serine-Threonine Kinases (EC 2.7.11.1) ; SCH9 protein, S cerevisiae (EC 2.7.11.1)
    Language English
    Publishing date 2011-04
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 184237-7
    ISSN 1470-8752 ; 0300-5127
    ISSN (online) 1470-8752
    ISSN 0300-5127
    DOI 10.1042/BST0390487
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: An alternative D. melanogaster 7SK snRNP.

    Nguyen, Duy / Buisine, Nicolas / Fayol, Olivier / Michels, Annemieke A / Bensaude, Olivier / Price, David H / Uguen, Patricia

    BMC molecular and cell biology

    2021  Volume 22, Issue 1, Page(s) 43

    Abstract: Background: The 7SK small nuclear RNA (snRNA) found in most metazoans is a key regulator of P-TEFb which in turn regulates RNA polymerase II elongation. Although its primary sequence varies in protostomes, its secondary structure and function are ... ...

    Abstract Background: The 7SK small nuclear RNA (snRNA) found in most metazoans is a key regulator of P-TEFb which in turn regulates RNA polymerase II elongation. Although its primary sequence varies in protostomes, its secondary structure and function are conserved across evolutionary distant taxa.
    Results: Here, we describe a novel ncRNA sharing many features characteristic of 7SK RNAs, in D. melanogaster. We examined the structure of the corresponding gene and determined the expression profiles of the encoded RNA, called snRNA:7SK:94F, during development. It is probably produced from the transcription of a lncRNA which is processed into a mature snRNA. We also addressed its biological function and we show that, like dm7SK, this alternative 7SK interacts in vivo with the different partners of the P-TEFb complex, i.e. HEXIM, LARP7 and Cyclin T. This novel RNA is widely expressed across tissues.
    Conclusion: We propose that two distinct 7SK genes might contribute to the formation of the 7SK snRNP complex in D. melanogaster.
    MeSH term(s) Animals ; Cyclin T/metabolism ; Drosophila Proteins/metabolism ; Drosophila melanogaster ; Positive Transcriptional Elongation Factor B/genetics ; Positive Transcriptional Elongation Factor B/metabolism ; Protein Binding ; RNA, Long Noncoding/genetics ; RNA, Long Noncoding/metabolism ; RNA, Small Nuclear/genetics ; RNA, Small Nuclear/metabolism ; RNA-Binding Proteins/metabolism ; Ribonucleoproteins/metabolism ; Ribonucleoproteins, Small Nuclear/metabolism ; Transcription Factors
    Chemical Substances CycT protein, Drosophila ; Cyclin T ; Drosophila Proteins ; HEXIM protein, Drosophila ; LARP7 protein, Drosophila ; RNA, Long Noncoding ; RNA, Small Nuclear ; RNA-Binding Proteins ; Ribonucleoproteins ; Ribonucleoproteins, Small Nuclear ; Transcription Factors ; Positive Transcriptional Elongation Factor B (EC 2.7.11.-)
    Language English
    Publishing date 2021-08-31
    Publishing country England
    Document type Journal Article
    ISSN 2661-8850
    ISSN (online) 2661-8850
    DOI 10.1186/s12860-021-00381-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: RNA-driven cyclin-dependent kinase regulation: when CDK9/cyclin T subunits of P-TEFb meet their ribonucleoprotein partners.

    Michels, Annemieke A / Bensaude, Olivier

    Biotechnology journal

    2008  Volume 3, Issue 8, Page(s) 1022–1032

    Abstract: The positive transcription elongation factor (P-TEFb) consists of CDK9, a cyclin-dependent kinase and its cyclin T partner. It is required for transcription of most class II genes. Its activity is regulated by non-coding RNAs. The 7SK cellular RNA turns ... ...

    Abstract The positive transcription elongation factor (P-TEFb) consists of CDK9, a cyclin-dependent kinase and its cyclin T partner. It is required for transcription of most class II genes. Its activity is regulated by non-coding RNAs. The 7SK cellular RNA turns the HEXIM cellular protein into a P-TEFb inhibitor that binds its cyclin T subunit. Thus, P-TEFb activity responds to variations in global cellular transcriptional activity and to physiological conditions linked to cell differentiation, proliferation or cardiac hypertrophy. In contrast, the Tat activation region RNA plays an activating role. This feature at the 5' end of the human immunodeficiency (HIV) viral transcript associates with the viral protein Tat that in turn binds cyclin T1 and recruits active P-TEFb to the HIV promoter. This results in enhanced P-TEFb activity, which is critical for an efficient production of viral transcripts. Although discovered recently, the regulation of P-TEFb becomes a paradigm for non-coding RNAs that regulate transcription factors. It is also a unique example of RNA-driven regulation of a cyclindependent kinase.
    MeSH term(s) Cyclin-Dependent Kinase 9/chemistry ; Cyclin-Dependent Kinase 9/metabolism ; Cyclins/chemistry ; Cyclins/metabolism ; Gene Expression Regulation, Enzymologic/physiology ; Positive Transcriptional Elongation Factor B/chemistry ; Positive Transcriptional Elongation Factor B/metabolism ; Protein Subunits ; RNA/chemistry ; RNA/metabolism ; Ribonucleoproteins/chemistry ; Ribonucleoproteins/metabolism ; Structure-Activity Relationship
    Chemical Substances Cyclins ; Protein Subunits ; Ribonucleoproteins ; RNA (63231-63-0) ; Positive Transcriptional Elongation Factor B (EC 2.7.11.-) ; Cyclin-Dependent Kinase 9 (EC 2.7.11.22)
    Language English
    Publishing date 2008-08
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 2221885-3
    ISSN 1860-7314 ; 1860-6768
    ISSN (online) 1860-7314
    ISSN 1860-6768
    DOI 10.1002/biot.200800104
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Does Pol I talk to Pol II? Coordination of RNA polymerases in ribosome biogenesis.

    Michels, Annemieke A / Hernandez, Nouria

    Genes & development

    2006  Volume 20, Issue 15, Page(s) 1982–1985

    MeSH term(s) RNA Polymerase I/physiology ; RNA Polymerase II/physiology ; RNA, Ribosomal, 5S/metabolism ; Ribosomes/metabolism ; Saccharomyces cerevisiae/genetics ; Saccharomyces cerevisiae/metabolism
    Chemical Substances RNA, Ribosomal, 5S ; RNA Polymerase II (EC 2.7.7.-) ; RNA Polymerase I (EC 2.7.7.6)
    Language English
    Publishing date 2006-08-01
    Publishing country United States
    Document type Journal Article ; Comment
    ZDB-ID 806684-x
    ISSN 1549-5477 ; 0890-9369
    ISSN (online) 1549-5477
    ISSN 0890-9369
    DOI 10.1101/gad.1460706
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Phosphorylation by casein kinase 2 facilitates rRNA gene transcription by promoting dissociation of TIF-IA from elongating RNA polymerase I.

    Bierhoff, Holger / Dundr, Miroslav / Michels, Annemieke A / Grummt, Ingrid

    Molecular and cellular biology

    2008  Volume 28, Issue 16, Page(s) 4988–4998

    Abstract: The protein kinase casein kinase 2 (CK2) phosphorylates different components of the RNA polymerase I (Pol I) transcription machinery and exerts a positive effect on rRNA gene (rDNA) transcription. Here we show that CK2 phosphorylates the transcription ... ...

    Abstract The protein kinase casein kinase 2 (CK2) phosphorylates different components of the RNA polymerase I (Pol I) transcription machinery and exerts a positive effect on rRNA gene (rDNA) transcription. Here we show that CK2 phosphorylates the transcription initiation factor TIF-IA at serines 170 and 172 (Ser170/172), and this phosphorylation triggers the release of TIF-IA from Pol I after transcription initiation. Inhibition of Ser170/172 phosphorylation or covalent tethering of TIF-IA to the RPA43 subunit of Pol I inhibits rDNA transcription, leading to perturbation of nucleolar structure and cell cycle arrest. Fluorescence recovery after photobleaching and chromatin immunoprecipitation experiments demonstrate that dissociation of TIF-IA from Pol I is a prerequisite for proper transcription elongation. In support of phosphorylation of TIF-IA switching from the initiation into the elongation phase, dephosphorylation of Ser170/172 by FCP1 facilitates the reassociation of TIF-IA with Pol I, allowing a new round of rDNA transcription. The results reveal a mechanism by which the functional interplay between CK2 and FCP1 sustains multiple rounds of Pol I transcription.
    MeSH term(s) Amino Acid Sequence ; Animals ; Casein Kinase II/metabolism ; Cell Cycle ; Cell Nucleolus/metabolism ; Cell Proliferation ; DNA, Ribosomal/genetics ; Humans ; Mice ; Models, Biological ; Molecular Sequence Data ; NIH 3T3 Cells ; Phosphoprotein Phosphatases/metabolism ; Phosphorylation ; Phosphoserine/metabolism ; Pol1 Transcription Initiation Complex Proteins ; Promoter Regions, Genetic/genetics ; Protein Binding ; RNA Polymerase I/metabolism ; RNA Precursors/biosynthesis ; RNA, Ribosomal/genetics ; Transcription Factors/chemistry ; Transcription Factors/metabolism ; Transcription, Genetic
    Chemical Substances DNA, Ribosomal ; Pol1 Transcription Initiation Complex Proteins ; RNA Precursors ; RNA, Ribosomal ; RRN3 protein, human ; Transcription Factors ; Phosphoserine (17885-08-4) ; Casein Kinase II (EC 2.7.11.1) ; RNA Polymerase I (EC 2.7.7.6) ; Phosphoprotein Phosphatases (EC 3.1.3.16) ; carboxy-terminal domain phosphatase (EC 3.1.3.16)
    Language English
    Publishing date 2008-06-16
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 779397-2
    ISSN 1098-5549 ; 0270-7306
    ISSN (online) 1098-5549
    ISSN 0270-7306
    DOI 10.1128/MCB.00492-08
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article: Immunosuppressive therapy after solid-organ transplantation: does the INTERMED identify patients at risk of poor adherence?

    Michaud, Laurent / Ludwig, Gundula / Berney, Sylvie / Rodrigues, Stéphanie / Niquille, Anne / Santschi, Valérie / Favre, Anne-Sophie / Lange, Anne-Catherine / Michels, Annemieke A / Vrijens, Bernard / Bugnon, Olivier / Pilon, Nathalie / Pascual, Manuel / Venetz, Jean-Pierre / Stiefel, Friedrich / Schneider, Marie-Paule

    Pharmacy practice

    2016  Volume 14, Issue 4, Page(s) 822

    Abstract: Background: Lack of adherence to medication is a trigger of graft rejection in solid-organ transplant (SOT) recipients.: Objective: This exploratory study aimed to assess whether a biopsychosocial evaluation using the INTERMED instrument before ... ...

    Abstract Background: Lack of adherence to medication is a trigger of graft rejection in solid-organ transplant (SOT) recipients.
    Objective: This exploratory study aimed to assess whether a biopsychosocial evaluation using the INTERMED instrument before transplantation could identify SOT recipients at risk of suboptimal post-transplantation adherence to immunosuppressant drugs. We hypothesized that complex patients (INTERMED>20) might have lower medication adherence than noncomplex patients (INTERMED≤20).
    Methods: Each patient eligible for transplantation at the University Hospital of Lausanne, Switzerland, has to undergo a pre-transplantation psychiatric evaluation. In this context the patient was asked to participate in our study. The INTERMED was completed pre-transplantation, and adherence to immunosuppressive medication was monitored post-transplantation by electronic monitors for 12 months. The main outcome measure was the implementation and persistence to two calcineurin inhibitors, cyclosporine and tacrolimus, according to the dichotomized INTERMED score (>20 or ≤20).
    Results: Among the 50 SOT recipients who completed the INTERMED, 32 entered the study. The complex (N=11) and noncomplex patients (N=21) were similar in terms of age, sex and transplanted organ. Implementation was 94.2% in noncomplex patients versus 87.8% in complex patients (non-significant p-value). Five patients were lost to follow-up: one was non-persistent, and four refused electronic monitoring. Of the four patients who refused monitoring, two were complex and withdrew early, and two were noncomplex and withdrew later in the study.
    Conclusion: Patients identified as complex pre-transplant by the INTERMED tended to deviate from their immunosuppressant regimen, but the findings were not statistically significant. Larger studies are needed to evaluate this association further, as well as the appropriateness of using a nonspecific biopsychosocial instrument such as INTERMED in highly morbid patients who have complex social and psychological characteristics.
    Language English
    Publishing date 2016-12-15
    Publishing country Spain
    Document type Journal Article
    ZDB-ID 2414565-8
    ISSN 1886-3655 ; 1885-642X
    ISSN (online) 1886-3655
    ISSN 1885-642X
    DOI 10.18549/PharmPract.2016.04.822
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: mTORC1 directly phosphorylates and regulates human MAF1.

    Michels, Annemieke A / Robitaille, Aaron M / Buczynski-Ruchonnet, Diane / Hodroj, Wassim / Reina, Jaime H / Hall, Michael N / Hernandez, Nouria

    Molecular and cellular biology

    2010  Volume 30, Issue 15, Page(s) 3749–3757

    Abstract: mTORC1 is a central regulator of growth in response to nutrient availability, but few direct targets have been identified. RNA polymerase (pol) III produces a number of essential RNA molecules involved in protein synthesis, RNA maturation, and other ... ...

    Abstract mTORC1 is a central regulator of growth in response to nutrient availability, but few direct targets have been identified. RNA polymerase (pol) III produces a number of essential RNA molecules involved in protein synthesis, RNA maturation, and other processes. Its activity is highly regulated, and deregulation can lead to cell transformation. The human phosphoprotein MAF1 becomes dephosphorylated and represses pol III transcription after various stresses, but neither the significance of the phosphorylations nor the kinase involved is known. We find that human MAF1 is absolutely required for pol III repression in response to serum starvation or TORC1 inhibition by rapamycin or Torin1. The protein is phosphorylated mainly on residues S60, S68, and S75, and this inhibits its pol III repression function. The responsible kinase is mTORC1, which phosphorylates MAF1 directly. Our results describe molecular mechanisms by which mTORC1 controls human MAF1, a key repressor of RNA polymerase III transcription, and add a new branch to the signal transduction cascade immediately downstream of TORC1.
    MeSH term(s) Humans ; Phosphorylation ; RNA Polymerase III/antagonists & inhibitors ; RNA Polymerase III/genetics ; RNA Polymerase III/metabolism ; Signal Transduction/drug effects ; Signal Transduction/genetics ; Sirolimus/metabolism ; Sirolimus/pharmacology ; Transfection
    Chemical Substances RNA Polymerase III (EC 2.7.7.6) ; Sirolimus (W36ZG6FT64)
    Language English
    Publishing date 2010-06-01
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 779397-2
    ISSN 1098-5549 ; 0270-7306
    ISSN (online) 1098-5549
    ISSN 0270-7306
    DOI 10.1128/MCB.00319-10
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Ubiquitination of HEXIM1 by HDM2.

    Lau, Joanne / Lew, Qiao Jing / Diribarne, Gaelle / Michels, Annemieke A / Dey, Anwesha / Bensaude, Olivier / Lane, David P / Chao, Sheng-Hao

    Cell cycle (Georgetown, Tex.)

    2009  Volume 8, Issue 14, Page(s) 2247–2254

    Abstract: Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) is an inhibitor of the positive transcription elongation factor b (P-TEFb), which controls RNA polymerase II transcription and human immunodeficiency virus Tat transactivation. In cells, more than ... ...

    Abstract Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) is an inhibitor of the positive transcription elongation factor b (P-TEFb), which controls RNA polymerase II transcription and human immunodeficiency virus Tat transactivation. In cells, more than half of P-TEFb is associated with HEXIM1 resulting in the inactivation of P-TEFb. Recently, we found that nucleophosmin (NPM), a key factor involved in p53 signaling pathway, interacts with HEXIM1 and activates P-TEFb-dependent transcription. Here we report that human double minute-2 protein (HDM2), a p53-specific E3 ubiquitin ligase, specifically ubiquitinates HEXIM1 through the lysine residues located within the basic region of HEXIM1. However, the HDM2-induced HEXIM1 ubiquitination does not lead to proteasome-mediated protein degradation. Fusion of ubiquitin to HEXIM1 demonstrates stronger inhibition on P-TEFb-dependent transcription. Our results demonstrate that HDM2 functions as a specific E3 ubiquitin ligase for HEXIM1, suggesting a possible role for HEXIM1 ubiquitination in the regulation of P-TEFb activity.
    MeSH term(s) Cell Line ; Cysteine Proteinase Inhibitors/pharmacology ; Humans ; Leupeptins/pharmacology ; Nuclear Proteins/metabolism ; Positive Transcriptional Elongation Factor B/genetics ; Positive Transcriptional Elongation Factor B/metabolism ; Proto-Oncogene Proteins c-mdm2/metabolism ; RNA-Binding Proteins/metabolism ; Signal Transduction ; Tumor Suppressor Protein p53/metabolism ; Ubiquitin-Protein Ligases/metabolism ; Ubiquitination
    Chemical Substances Cysteine Proteinase Inhibitors ; HEXIM1 protein, human ; Leupeptins ; Nuclear Proteins ; RNA-Binding Proteins ; Tumor Suppressor Protein p53 ; nucleophosmin (117896-08-9) ; MDM2 protein, human (EC 2.3.2.27) ; Proto-Oncogene Proteins c-mdm2 (EC 2.3.2.27) ; Ubiquitin-Protein Ligases (EC 2.3.2.27) ; Positive Transcriptional Elongation Factor B (EC 2.7.11.-) ; benzyloxycarbonylleucyl-leucyl-leucine aldehyde (RF1P63GW3K)
    Language English
    Publishing date 2009-08-05
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2146183-1
    ISSN 1551-4005 ; 1538-4101 ; 1554-8627
    ISSN (online) 1551-4005
    ISSN 1538-4101 ; 1554-8627
    DOI 10.4161/cc.8.14.9015
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Inhibition of Tat activity by the HEXIM1 protein

    Majello Barbara / Michels Annemieke A / Napolitano Giuliana / Varrone Francesca / Fraldi Alessandro / Bensaude Olivier / Lania Luigi

    Retrovirology, Vol 2, Iss 1, p

    2005  Volume 42

    Abstract: Abstract Background The positive transcription elongation factor b (P-TEFb) composed by CDK9/CyclinT1 subunits is a dedicated co-factor of HIV transcriptional transactivator Tat protein. Transcription driven by the long terminal repeat (LTR) of HIV ... ...

    Abstract Abstract Background The positive transcription elongation factor b (P-TEFb) composed by CDK9/CyclinT1 subunits is a dedicated co-factor of HIV transcriptional transactivator Tat protein. Transcription driven by the long terminal repeat (LTR) of HIV involves formation of a quaternary complex between P-TEFb, Tat and the TAR element. This recruitment is necessary to enhance the processivity of RNA Pol II from the HIV-1 5' LTR promoter. The activity of P-TEFb is regulated in vivo and in vitro by the HEXIM1/7SK snRNA ribonucleic-protein complex. Results Here we report that Tat transactivation is effectively inhibited by co-expression of HEXIM1 or its paralog HEXIM2. HEXIM1 expression specifically represses transcription mediated by the direct activation of P-TEFb through artificial recruitment of GAL4-CycT1. Using appropriate HEXIM1 mutants we determined that effective Tat-inhibition entails the 7SK snRNA basic recognition motif as well as the C-terminus region required for interaction with cyclin T1. Enhanced expression of HEXIM1 protein modestly affects P-TEFb activity, suggesting that HEXIM1-mediated repression of Tat activity is not due to a global inhibition of cellular transcription. Conclusion These results point to a pivotal role of P-TEFb for Tat's optimal transcription activity and suggest that cellular proteins that regulate P-TEFb activity might exert profound effects on Tat function in vivo .
    Keywords Medicine (General) ; R5-920 ; Medicine ; R ; DOAJ:Medicine (General) ; DOAJ:Health Sciences ; Immunologic diseases. Allergy ; RC581-607
    Subject code 570 ; 571
    Language English
    Publishing date 2005-07-01T00:00:00Z
    Publisher BioMed Central
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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