Analysis of Primer Extension and the First Template Switch during Human Immunodeficiency Virus Reverse Transcription

1995 ◽  
Vol 2 (4) ◽  
pp. 314-321
Author(s):  
Eric J. Arts (a,b) ◽  
Zhou Li ◽  
Mark A. Wainberg
Virology ◽  
2002 ◽  
Vol 300 (2) ◽  
pp. 226-235 ◽  
Author(s):  
C.William Hooker ◽  
Julie Scott ◽  
Ann Apolloni ◽  
Emma Parry ◽  
David Harrich

2005 ◽  
Vol 79 (4) ◽  
pp. 2199-2210 ◽  
Author(s):  
Yan Zhou ◽  
Haili Zhang ◽  
Janet D. Siliciano ◽  
Robert F. Siliciano

ABSTRACT In untreated human immunodeficiency virus type 1 (HIV-1) infection, most viral genomes in resting CD4+ T cells are not integrated into host chromosomes. This unintegrated virus provides an inducible latent reservoir because cellular activation permits integration, virus gene expression, and virus production. It remains controversial whether HIV-1 is stable in this preintegration state. Here, we monitored the fate of HIV-1 in resting CD4+ cells by using a green fluorescent protein (GFP) reporter virus carrying an X4 envelope. After virus entry into resting CD4+ T cells, both rescuable virus gene expression, visualized with GFP, and rescuable virion production, assessed by p24 release, decayed with a half-life of 2 days. In these cells, reverse transcription goes to completion over 2 to 3 days, and 50% of the viruses that have entered undergo functional decay before reverse transcription is complete. We distinguished two distinct but closely related factors contributing to loss of rescuable virus. First, some host cells undergo virus-induced apoptosis upon viral entry, thereby reducing the amount of rescuable virus. Second, decay processes directly affecting the virus both before and after the completion of reverse transcription contribute to the loss of rescuable virus. The functional half-life of full-length, integration-competent reverse transcripts is only 1 day. We propose that rapid intracellular decay processes compete with early steps in viral replication in infected CD4+ T cells. Decay processes dominate in resting CD4+ T cells as a result of the slow kinetics of reverse transcription and blocks at subsequent steps. Therefore, the reservoir of unintegrated HIV-1 in recently infected resting CD4+ T cells is highly labile.


Blood ◽  
1997 ◽  
Vol 90 (3) ◽  
pp. 1141-1149 ◽  
Author(s):  
Tessie B. McNeely ◽  
Diane C. Shugars ◽  
Mary Rosendahl ◽  
Christina Tucker ◽  
Stephen P. Eisenberg ◽  
...  

Abstract Infection of monocytes with human immunodeficiency virus type 1Ba-L (HIV-1Ba-L ) is significantly inhibited by treatment with the serine protease inhibitor, secretory leukocyte protease inhibitor (SLPI). SLPI does not appear to act on virus directly, but rather the inhibitory activity is most likely due to interaction with the host cell. The current study was initiated to investigate how SLPI interacts with monocytes to inhibit infection. SLPI was found to bind to monocytes with high affinity to a single class of receptor sites (∼7,000 receptors per monocyte, KD = 3.6 nmol/L). The putative SLPI receptor was identified as a surface protein with a molecular weight of 55 ± 5 kD. A well-characterized function of SLPI is inhibition of neutrophil elastase and cathepsin G. However, two SLPI mutants (or muteins) that contain single amino acid substitutions and exhibit greatly reduced protease inhibitory activity still bound to monocytes and retained anti–HIV-1 activity. SLPI consists of two domains, of which the C-terminal domain contains the protease inhibiting region. However, when tested independently, neither domain had potent anti–HIV-1 activity. SLPI binding neither prevented virus binding to monocytes nor attenuated the infectivity of any virus progeny that escaped inhibition by SLPI. A polymerase chain reaction (PCR)-based assay for newly generated viral DNA demonstrated that SLPI blocks at or before viral DNA synthesis. Therefore, it most likely inhibits a step of viral infection that occurs after virus binding but before reverse transcription. Taken together, the unique antiviral activity of SLPI, which may be independent of its previously characterized antiprotease activity, appears to reside in disruption of the viral infection process soon after virus binding.


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