scholarly journals Heterologous Late-Domain Sequences Have Various Abilities To Promote Budding of Human Immunodeficiency Virus Type 1

2005 ◽  
Vol 79 (14) ◽  
pp. 9038-9045 ◽  
Author(s):  
David E. Ott ◽  
Lori V. Coren ◽  
Tracy D. Gagliardi ◽  
Kunio Nagashima

ABSTRACT Retroviral late (L) domains present within Gag act in conjunction with cellular proteins to efficiently release virions from the surface of the cell. Three different critical core sequences have been identified as required elements for L-domain function: PPPY, PTAP (also PSAP), and YPDL, with different retroviruses utilizing one or two of these core sequences. The human immunodeficiency virus type 1 (HIV-1) L domain is centered around a PTAP sequence in the p6 region of Gag. To assess the ability of heterologous L-domain sequences to be functionally interchanged for those in full-length HIV-1, we produced a series of constructs that replaced PTAP-containing p6Gag sequences with those of PPPY- or YPDL-based L domains. While previous studies had found that L domains are interchangeable in other retroviruses, most of the sequences introduced into p6Gag failed to substitute for PTAP-mediated L-domain function. One exception was the 11-amino-acid p2b sequence of Rous sarcoma virus (RSV) Gag, which could fully restore HIV-1 budding, while a PPPPY sequence exchange alone did not. This suggests that the RSV L domain consists of more than simply its core L-domain sequence. The HIV-p2b chimera was as infectious as the wild type, produced normal virions, and was sensitive to proteasome inhibitors. These results show that L-domain sequences are not necessarily interchangeable. Thus, HIV-1 Gag might have a more stringent requirement for L-domain function than the other retroviruses previously studied.

2006 ◽  
Vol 81 (3) ◽  
pp. 1534-1536 ◽  
Author(s):  
Mingli Qi ◽  
Christopher Aiken

ABSTRACT The Nef protein enhances human immunodeficiency virus type 1 (HIV-1) infectivity by facilitating an early postentry step in the virus life cycle. We report here that the addition of MG132 or lactacystin, each a specific inhibitor of cellular proteasome activity, preferentially enhances cellular permissiveness to infection by Nef-defective versus wild-type HIV-1. Pseudotyping by the glycoprotein of vesicular stomatitis virus rendered Nef-defective HIV-1 particles minimally responsive to the enhancing effects of proteasome inhibitors. These results suggest that Nef enhances the infectivity of HIV-1 particles by reducing their susceptibility to proteasomal degradation in target cells.


2007 ◽  
Vol 82 (5) ◽  
pp. 2575-2579 ◽  
Author(s):  
Jenny L. Anderson ◽  
Edward M. Campbell ◽  
Anna Figueiredo ◽  
Thomas J. Hope

ABSTRACT TRIM5α restriction factors protect target cells from retroviruses by blocking infection prior to the accumulation of viral reverse transcription (RT) products. Here, we demonstrate that heat shock perturbed owl monkey TRIMCyp and rhesus TRIM5α-mediated restriction of human immunodeficiency virus type 1 (HIV-1) late RT products and 2-long terminal repeat circles. Heat shock partially rescued HIV-1 infection from TRIMCyp restriction, and this rescue became more profound when combined with the presence of the proteasome inhibitor MG132. This indicates that viral RT products rescued from restriction by either heat shock treatment or the presence of MG132 are on a productive pathway, supporting a model in which TRIM5α proteins restrict retroviruses in multiple phases that are differentially sensitive to heat shock and proteasome inhibitors.


1994 ◽  
Vol 70 (6) ◽  
Author(s):  
Marisa Márcia Mussi-Pinhata ◽  
Maria Célia C. Ferez ◽  
Dimas T. Covas ◽  
Geraldo Duarte ◽  
Márcia L. Isaac ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1798
Author(s):  
Grant R. Campbell ◽  
Stephen A. Spector

Effective antiretroviral therapy has led to significant human immunodeficiency virus type 1 (HIV-1) suppression and improvement in immune function. However, the persistence of integrated proviral DNA in latently infected reservoir cells, which drive viral rebound post-interruption of antiretroviral therapy, remains the major roadblock to a cure. Therefore, the targeted elimination or permanent silencing of this latently infected reservoir is a major focus of HIV-1 research. The most studied approach in the development of a cure is the activation of HIV-1 expression to expose latently infected cells for immune clearance while inducing HIV-1 cytotoxicity—the “kick and kill” approach. However, the complex and highly heterogeneous nature of the latent reservoir, combined with the failure of clinical trials to reduce the reservoir size casts doubt on the feasibility of this approach. This concern that total elimination of HIV-1 from the body may not be possible has led to increased emphasis on a “functional cure” where the virus remains but is unable to reactivate which presents the challenge of permanently silencing transcription of HIV-1 for prolonged drug-free remission—a “block and lock” approach. In this review, we discuss the interaction of HIV-1 and autophagy, and the exploitation of autophagy to kill selectively HIV-1 latently infected cells as part of a cure strategy. The cure strategy proposed has the advantage of significantly decreasing the size of the HIV-1 reservoir that can contribute to a functional cure and when optimised has the potential to eradicate completely HIV-1.


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