Host SAMHD1 Protein Promotes HIV-1 Recombination in Macrophages

• Type of Material: Article
• Authors: Laura A. Nguyen, University of Rochester; Dong-Hyun Kim, Kyung Hee University; Michele B. Daly, Emory University; Kevin C. Allan, University of Rochester; Baek Kim, Emory University
• Language: English
• Date: 2014-01-31
• Publisher: American Society for Biochemistry and Molecular Biology
• Publication Version: Final Published Version
• Copyright Statement: © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.
• Final Published Version (URL): http://dx.doi.org/10.1074/jbc.C113.522326
• Title of Journal or Parent Work: Journal of Biological Chemistry
• ISSN: 0021-9258
• Volume: 289
• Issue: 5
• Start Page: 2489
• End Page: 2496
• Grant/Funding Information: This work was supported, in whole or in part, by National Institutes of Health Grants AI077401 and AI049781 (to B. K.).; This work was also supported by the Emory Center for AIDS Research.
• Keywords: RESTRICTION FACTOR SAMHD1; DENDRITIC CELLS; RNASE-H; REVERSE-TRANSCRIPTASE MUTANT; HIV-1; Vpx; Life Sciences & Biomedicine; Science & Technology; IMMUNODEFICIENCY-VIRUS TYPE-1; Reverse Transcription; DNA-SYNTHESIS; Biochemistry & Molecular Biology; GENETIC-RECOMBINATION; BIOCHEMISTRY & MOLECULAR BIOLOGY; Homologous Recombination; Nucleotide; SAMHD1; CELLULAR DNTP CONCENTRATIONS; STRAND TRANSFER; Macrophages; T-LYMPHOCYTES
• Research Categories: Biology, Genetics; Biology, Virology; Chemistry, Biochemistry

Abstract

Template switching can occur during the reverse transcription of HIV-1. Deoxynucleotide triphosphate (dNTP) concentrations have been biochemically shown to impact HIV-1 reverse transcriptase (RT)-mediated strand transfer. Lowering the dNTP concentrations promotes RT pausing and RNA template degradation by RNase H activity of the RT, subsequently leading to strand transfer. Terminally differentiated/nondividing macrophages, which serve as a key HIV-1 reservoir, contain extremely low dNTP concentrations (20-50 nM), which results from the cellular dNTP hydrolyzing sterile α motif and histidine aspartic domain containing protein 1 (SAMHD1) protein, when compared with activated CD4 + T cells (2-5 μM). In this study, we first observed that HIV-1 template switching efficiency was nearly doubled in human primary macrophages when compared with activated CD4+ T cells. Second, SAMHD1 degradation by viral protein X (Vpx), which elevates cellular dNTP concentrations, decreased HIV-1 template switching efficiency in macrophages to the levels comparable with CD4+ T cells. Third, differentiated SAMHD1 shRNA THP-1 cells have a 2-fold increase in HIV-1 template switching efficiency. Fourth, SAMHD1 degradation by Vpx did not alter HIV-1 template switching efficiency in activated CD4+ T cells. Finally, the HIV-1 V148I RT mutant that is defective in dNTP binding and has DNA synthesis delay promoted RT stand transfer when compared with wild type RT, particularly at low dNTP concentrations. Here, we report that SAMHD1 regulation of the dNTP concentrations influences HIV-1 template switching efficiency, particularly in macrophages.