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Identification of a Structural Element in HIV-1 Gag Required for Virus Particle Assembly and Maturation

Novikova, Mariia and Adams, Lucas J. and Fontana, Juan and Gres, Anna T. and Balasubramaniam, Muthukumar and Winkler, Dennis C. and Kudchodkar, Sagar B. and Soheilian, Ferri and Sarafianos, Stefan G. and Steven, Alasdair C. and Freed, Eric O. (2018) Identification of a Structural Element in HIV-1 Gag Required for Virus Particle Assembly and Maturation. mBio, 9 (5). Art. No. e01567-18. ISSN 2150-7511. PMCID PMC6191540. https://resolver.caltech.edu/CaltechAUTHORS:20181023-104225603

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Abstract

Late in the HIV-1 replication cycle, the viral structural protein Gag is targeted to virus assembly sites at the plasma membrane of infected cells. The capsid (CA) domain of Gag plays a critical role in the formation of the hexameric Gag lattice in the immature virion, and, during particle release, CA is cleaved from the Gag precursor by the viral protease and forms the conical core of the mature virion. A highly conserved Pro-Pro-Ile-Pro (PPIP) motif (CA residues 122 to 125) [PPIP(122–125)] in a loop connecting CA helices 6 and 7 resides at a 3-fold axis formed by neighboring hexamers in the immature Gag lattice. In this study, we characterized the role of this PPIP(122–125) loop in HIV-1 assembly and maturation. While mutations P123A and P125A were relatively well tolerated, mutation of P122 and I124 significantly impaired virus release, caused Gag processing defects, and abolished infectivity. X-ray crystallography indicated that the P122A and I124A mutations induce subtle changes in the structure of the mature CA lattice which were permissive for in vitro assembly of CA tubes. Transmission electron microscopy and cryo-electron tomography demonstrated that the P122A and I124A mutations induce severe structural defects in the immature Gag lattice and abrogate conical core formation. Propagation of the P122A and I124A mutants in T-cell lines led to the selection of compensatory mutations within CA. Our findings demonstrate that the CA PPIP(122–125) loop comprises a structural element critical for the formation of the immature Gag lattice.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1128/mbio.01567-18DOIArticle
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6191540/PubMed CentralArticle
ORCID:
AuthorORCID
Fontana, Juan0000-0002-9084-2927
Additional Information:This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply. Received 18 July 2018; Accepted 12; September 2018; Published 16 October 2018. We thank members of the Freed laboratory for helpful discussion and critical review of the manuscript. This work was supported by the Intramural Research Programs of the Center for Cancer Research, National Cancer Institute, NIH (E.O.F.), and the National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH (A.C.S.); by the Intramural AIDS Targeted Antiviral Program (E.O.F. and A.C.S.), National Institute of Allergy and Infectious Diseases (R01-AI120860, R21-AI112417, and U54 GM103368), NIH (S.G.S.); and by the University of Leeds (University Academic Fellow scheme; J.F.). This project has been funded in whole or in part with federal funds from the National Cancer Institute, National Institutes of Health, under contract HHSN26120080001E. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.
Funders:
Funding AgencyGrant Number
NIHR01-AI120860
NIHR21-AI112417
NIHU54 GM103368
University of LeedsUNSPECIFIED
NIHHHSN26120080001E
Subject Keywords:cryo-EM; HIV-1; assembly; capsid; maturation; virus replication
Issue or Number:5
PubMed Central ID:PMC6191540
Record Number:CaltechAUTHORS:20181023-104225603
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20181023-104225603
Official Citation:Identification of a Structural Element in HIV-1 Gag Required for Virus Particle Assembly and Maturation. Mariia Novikova, Lucas J. Adams, Juan Fontana, Anna T. Gres, Muthukumar Balasubramaniam, Dennis C. Winkler, Sagar B. Kudchodkar, Ferri Soheilian, Stefan G. Sarafianos, Alasdair C. Steven, Eric O. Freed. mBio Oct 2018, 9 (5) e01567-18; DOI: 10.1128/mBio.01567-18
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90361
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:23 Oct 2018 19:41
Last Modified:03 Oct 2019 20:24

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