A mutant tat protein inhibits HIV-1 reverse transcription by targeting the reverse transcription complex

Lin, Min-Hsuan, Apolloni, Ann, Cutillas, Vincent, Sivakumaran, Haran, Martin, Sally, Li, Dongsheng, Wei, Ting, Wang, Rui, Jin, Hongping, Spann, Kirsten and Harrich, David (2015) A mutant tat protein inhibits HIV-1 reverse transcription by targeting the reverse transcription complex. Journal of Virology, 89 9: 4827-4836. doi:10.1128/JVI.03440-14

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Author Lin, Min-Hsuan
Apolloni, Ann
Cutillas, Vincent
Sivakumaran, Haran
Martin, Sally
Li, Dongsheng
Wei, Ting
Wang, Rui
Jin, Hongping
Spann, Kirsten
Harrich, David
Title A mutant tat protein inhibits HIV-1 reverse transcription by targeting the reverse transcription complex
Journal name Journal of Virology   Check publisher's open access policy
ISSN 1098-5514
Publication date 2015-05
Year available 2015
Sub-type Article (original research)
DOI 10.1128/JVI.03440-14
Open Access Status File (Publisher version)
Volume 89
Issue 9
Start page 4827
End page 4836
Total pages 10
Place of publication Washington, DC, United States
Publisher American Society for Microbiology
Collection year 2016
Language eng
Formatted abstract
Previously, we reported that a mutant of Tat referred to as Nullbasic inhibits HIV-1 reverse transcription although the mechanism of action is unknown. Here we show that Nullbasic is a reverse transcriptase (RT) binding protein that targets the reverse transcription complex rather than directly inhibiting RT activity. An interaction between Nullbasic and RT was observed by using coimmunoprecipitation and pulldown assays, and a direct interaction was measured by using a biolayer interferometry assay. Mixtures of recombinant 6×His-RT and Nullbasic-FLAG-V5-6×His at molar ratios of up to 1:20,000 did not inhibit RT activity in standard homopolymer primer template assays. An analysis of virus made by cells that coexpressed Nullbasic showed that Nullbasic copurified with virus particles, indicating that it was a virion protein. In addition, analysis of reverse transcription complexes (RTCs) isolated from cells infected with wild type or Nullbasic-treated HIV-1 showed that Nullbasic reduced the levels of viral DNA in RTC fractions. In addition, a shift in the distribution of viral DNA and CAp24 to less-dense non-RTC fractions was observed, indicating that RTC activity from Nullbasic-treated virus was impaired. Further analysis showed that viral cores isolated from Nullbasic-treated HIV undergo increased disassembly in vitro compared to untreated HIV-1. To our knowledge, this is the first description of an antiviral protein that inhibits reverse transcription by targeting the RTC and affecting core stability.

IMPORTANCE HIV-1 infection is treated by using combinations of antiretroviral drugs that target independent steps of virus replication. A newly described antiviral protein called Nullbasic can also inhibit a combination of different steps in virus replication (transcription, reverse transcription, and Rev-mediated viral mRNA transport), although the precise mechanism of action is unknown. This study shows that Nullbasic can inhibit reverse transcription by binding to the viral enzyme called reverse transcriptase, which results in accelerated uncoating of the viral core and instability of the viral apparatus called the reverse transcription complex (RTC). This unique antiviral activity may inform development of other RTC inhibitors, as well as providing a unique investigative tool for dissecting the RTC cellular composition.
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Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Queensland Brain Institute Publications
Official 2016 Collection
School of Biomedical Sciences Publications
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Citation counts: TR Web of Science Citation Count  Cited 3 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 2 times in Scopus Article | Citations
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