Deep Sequencing of HIV-1 Reverse Transcripts Reveals the Multifaceted Antiviral Functions of APOBEC3G

Nat Microbiol. 2018 Feb;3(2):220-233. doi: 10.1038/s41564-017-0063-9. Epub 2017 Nov 20.

Abstract

Following cell entry, the RNA genome of HIV-1 is reverse transcribed into double-stranded DNA that ultimately integrates into the host-cell genome to establish the provirus. These early phases of infection are notably vulnerable to suppression by a collection of cellular antiviral effectors, called restriction or resistance factors. The host antiviral protein APOBEC3G (A3G) antagonizes the early steps of HIV-1 infection through the combined effects of inhibiting viral cDNA production and cytidine-to-uridine-driven hypermutation of this cDNA. In seeking to address the underlying molecular mechanism for inhibited cDNA synthesis, we developed a deep sequencing strategy to characterize nascent reverse transcription products and their precise 3'-termini in HIV-1 infected T cells. Our results demonstrate site- and sequence-independent interference with reverse transcription, which requires the specific interaction of A3G with reverse transcriptase itself. This approach also established, contrary to current ideas, that cellular uracil base excision repair (UBER) enzymes target and cleave A3G-edited uridine-containing viral cDNA. Together, these findings yield further insights into the regulatory interplay between reverse transcriptase, A3G and cellular DNA repair machinery, and identify the suppression of HIV-1 reverse transcriptase by a directly interacting host protein as a new cell-mediated antiviral mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • APOBEC-3G Deaminase / chemistry
  • APOBEC-3G Deaminase / pharmacology*
  • Antiviral Agents / chemistry
  • Antiviral Agents / pharmacology*
  • DNA Repair
  • DNA, Complementary / metabolism
  • DNA, Viral / genetics
  • HEK293 Cells
  • HIV Infections
  • HIV Reverse Transcriptase / drug effects*
  • HIV-1 / genetics*
  • HIV-1 / pathogenicity
  • High-Throughput Nucleotide Sequencing / methods*
  • Humans
  • Protein Interaction Domains and Motifs
  • Reverse Transcription
  • T-Lymphocytes / virology
  • Virus Replication / drug effects

Substances

  • Antiviral Agents
  • DNA, Complementary
  • DNA, Viral
  • reverse transcriptase, Human immunodeficiency virus 1
  • HIV Reverse Transcriptase
  • APOBEC-3G Deaminase
  • APOBEC3G protein, human