Insights into HIV-1 proviral transcription from the structure and dynamics of the Tat:AFF4:P-TEFb:TAR complex

Abstract
Article and author information
Metrics

Abstract

HIV-1 Tat hijacks the human superelongation complex (SEC) to promote proviral transcription. Here we report the 5.9 Å structure of HIV-1 TAR in complex with HIV-1 Tat and human AFF4, CDK9, and CycT1. The TAR central loop contacts the CycT1 Tat-TAR recognition motif (TRM) and the second Tat Zn²⁺-binding loop. Hydrogen-deuterium exchange (HDX) shows that AFF4 helix 2 is stabilized in the TAR complex despite not touching the RNA, explaining how it enhances TAR binding to the SEC 50-fold. RNA SHAPE and SAXS data were used to help model the extended (Tat Arginine-Rich Motif) ARM, which enters the TAR major groove between the bulge and the central loop. The structure and functional assays collectively support a bipartite model, wherein the TAR central loop engages the CycT1 TRM and compact core of Tat, while the TAR major groove interacts with the extended Tat ARM.

Article and author information

Author details

Ursula Schulze-Gahmen

Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States

Competing interests
The authors declare that no competing interests exist.
Ignacia Echeverria

Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0003-4717-1467
Goran Stjepanovic

Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-4841-9949
Yun Bai

Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States

Competing interests
The authors declare that no competing interests exist.
Huasong Lu

Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States

Competing interests
The authors declare that no competing interests exist.
Dina Schneidman-Duhovny

Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States

Competing interests
The authors declare that no competing interests exist.
Jennifer A Doudna

Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States

Competing interests
The authors declare that no competing interests exist.
Qiang Zhou

Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States

Competing interests
The authors declare that no competing interests exist.
Andrej Sali

Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States

Competing interests
The authors declare that no competing interests exist.
James H Hurley

Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States

For correspondence
jimhurley@berkeley.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-5054-5445

Funding

National Institute of General Medical Sciences

James H Hurley

National Institute of Allergy and Infectious Diseases

Qiang Zhou

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

Copyright

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.