1. Biochemistry and Chemical Biology
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The HIV-1 Tat protein recruits a ubiquitin ligase to reorganize the 7SK snRNP for transcriptional activation

  1. Tyler B Faust
  2. Yang Li
  3. Curtis W Bacon
  4. Gwendolyn M Jang
  5. Amit Weiss
  6. Bhargavi Jayaraman
  7. Billy W Newton
  8. Nevan J Krogan
  9. Iván D'Orso
  10. Alan D Frankel  Is a corresponding author
  1. University of California, San Francisco, United States
  2. University of Texas Southwestern Medical Center, United States
  3. University of California San Francisco, United States
Research Article
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Cite this article as: eLife 2018;7:e31879 doi: 10.7554/eLife.31879

Abstract

The HIV-1 Tat protein hijacks P-TEFb kinase to activate paused RNA polymerase II (RNAP II) at the viral promoter. Tat binds additional host factors, but it is unclear how they regulate RNAP II elongation. Here we identify the cytoplasmic ubiquitin ligase UBE2O as critical for Tat transcriptional activity. Tat hijacks UBE2O to ubiquitinate the P-TEFb kinase inhibitor HEXIM1 of the 7SK snRNP, a fraction of which also resides in the cytoplasm bound to P-TEFb. HEXIM1 ubiquitination sequesters it in the cytoplasm and releases P-TEFb from the inhibitory 7SK complex. Free P-TEFb then becomes enriched in chromatin, a process that is also stimulated by treating cells with a CDK9 inhibitor. Finally, we demonstrate that UBE2O is critical for P-TEFb recruitment to the HIV-1 promoter. Together, the data support a unique model of elongation control where non-degradative ubiquitination of nuclear and cytoplasmic 7SK snRNP pools increases P-TEFb levels for transcriptional activation.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files.

Article and author information

Author details

  1. Tyler B Faust

    Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Yang Li

    Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Curtis W Bacon

    Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Gwendolyn M Jang

    Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Amit Weiss

    Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Bhargavi Jayaraman

    Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Billy W Newton

    Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Nevan J Krogan

    Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, United States
    Competing interests
    The authors declare that no competing interests exist.
  9. Iván D'Orso

    Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1409-2351
  10. Alan D Frankel

    Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
    For correspondence
    frankel@cgl.ucsf.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2525-9508

Funding

National Institute of General Medical Sciences (P50GM082250)

  • Nevan J Krogan
  • Alan D Frankel

National Institute of Allergy and Infectious Diseases (RO1AI114362)

  • Iván D'Orso

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Katherine A Jones, Salk Institute for Biological Studies, United States

Publication history

  1. Received: September 12, 2017
  2. Accepted: May 26, 2018
  3. Accepted Manuscript published: May 30, 2018 (version 1)
  4. Version of Record published: June 13, 2018 (version 2)

Copyright

© 2018, Faust et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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