Virion-associated, host-derived DHX9/RNA helicase A enhances the processivity of HIV-1 reverse transcriptase on genomic RNA

Samantha Brady, Gatikrushna Singh, Cheryl Bolinger, Zhenwei Song, Ioana Boeras, Kexin Weng, Bria Trent, William Clay Brown, Kamalendra Singh, Kathleen Boris-Lawrie, Xiao Heng

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

DHX9/RNA helicase A (RHA) is a host RNA helicase that participates in many critical steps of the HIV-1 life cycle. It co-assembles with the viral RNA genome into the capsid core. Virions deficient in RHA are less infectious as a result of reduced reverse transcription efficiency, demonstrating that the virion-associated RHA promotes reverse transcription before the virion gains access to the new host’s RHA. Here, we quantified reverse-transcription intermediates in HIV-1–infected T cells to clarify the mechanism by which RHA enhances HIV-1 reverse transcription efficiency. Consistently, purified recombinant human RHA promoted reverse transcription efficiency under in vitro conditions that mimic the early reverse transcription steps prior to capsid core uncoating. We did not observe RHA-mediated structural remodeling of the tRNALys3–viral RNA-annealed complex. RHA did not enhance the DNA synthesis rate until incorporation of the first few nucleotides, suggesting that RHA participates primarily in the elongation phase of reverse transcription. Pre–steady-state and steady-state kinetic studies revealed that RHA has little impact on the kinetics of single-nucleotide incorporation. Primer extension assays performed in the presence of trap dsDNA disclosed that RHA enhances the processivity of HIV-1 reverse transcriptase (RT). The biochemical assays used here effectively reflected and explained the low RT activity in HIV-1 virions produced from RHA-depleted cells. Moreover, RT activity in our assays indicated that RHA in HIV-1 virions is required for the efficient catalysis of ()cDNA synthesis during viral infection before capsid uncoating. Our study identifies RHA as a processivity factor of HIV-1 RT.

Original languageEnglish (US)
Pages (from-to)11473-11485
Number of pages13
JournalJournal of Biological Chemistry
Volume294
Issue number30
Early online dateJun 7 2019
DOIs
StatePublished - Jul 26 2019

Bibliographical note

Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Keywords

  • Host-pathogen
  • Host cell factors
  • Gene regulation

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural

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