Human immunodeficiency virus type 1 Nef protein is incorporated into virus particles and specifically cleaved by the viral proteinase.

@article{Welker1996HumanIV,
  title={Human immunodeficiency virus type 1 Nef protein is incorporated into virus particles and specifically cleaved by the viral proteinase.},
  author={Reinhold Welker and Hubert Kottler and Hans Robert Kalbitzer and Hans‐Georg Kr{\"a}usslich},
  journal={Virology},
  year={1996},
  volume={219 1},
  pages={
          228-36
        }
}
The Nef protein of primate immunodeficiency viruses is essential for establishing a highly productive pathogenic infection in vivo. In tissue culture, Nef is not required for infection but enhances viral infectivity. This effect is most pronounced in unstimulated primary lymphocytes and occurs in the early phase of infection prior to viral gene expression. Since Nef expression does not lead to obvious changes in virus composition, it was of interest to analyze whether Nef is incorporated into… 

Human Immunodeficiency Virus Type 1 Nef Incorporation into Virions Does Not Increase Infectivity

TLDR
It is demonstrated that the presence of Nef in viral particles is not sufficient to increase human immunodeficiency virus type 1 infectivity and suggested that Nef plays a role during the biogenesis of viral particles.

Virion Incorporation of Human Immunodeficiency Virus Type 1 Nef Is Mediated by a Bipartite Membrane-Targeting Signal: Analysis of Its Role in Enhancement of Viral Infectivity

TLDR
Results indicate that Nef incorporation into HIV-1 particles is mediated by plasma membrane targeting via an N-terminal bipartite signal which is reminiscent of a Src homology region 4.

The Proteolytic Cleavage of Human Immunodeficiency Virus Type 1 Nef Does Not Correlate with Its Ability To Stimulate Virion Infectivity

TLDR
It is concluded that the proteolytic processing of Nef is not required for the ability of this protein to enhance virion infectivity and simian immunodeficiency virus Nef, which lacks the sequence recognized by the protease and as a consequence is not cleaved despite its incorporation into virions, could stimulate the infectivity of a nef-defective HIV-1 variant as efficiently as HIV- 1 Nef.

Neurovirulent simian immunodeficiency virus incorporates a Nef-associated kinase activity into virions.

TLDR
Results suggest that selection for specific nef sequences occurs in vivo and has a significant effect on virus replication in specific cells and organs.

Association of Nef with the Human Immunodeficiency Virus Type 1 Core

TLDR
It is demonstrated that Nef stably associates with the HIV-1 core and suggested that virion-associated Nef plays a functional role in accelerating HIV- 1 replication.

Nef Enhances Human Immunodeficiency Virus Type 1 Infectivity Resulting from Intervirion Fusion: Evidence Supporting a Role for Nef at the Virion Envelope

TLDR
A potential mechanism for enhancing HIV-1 diversity in vivo through the rescue of defective viral genomes is revealed and a novel genetic system for the functional analysis of virion-associated proteins in HIV- 1 infection is provided.

Cell death induced by the herpes simplex virus-1 thymidine kinase delivered by human immunodeficiency virus-1-based virus-like particles.

Disassembly of Human Immunodeficiency Virus Type 1 Cores In Vitro Reveals Association of Nef with the Subviral Ribonucleoprotein Complex

TLDR
Results indicate that Nef interacts tightly with an internal component of the HIV-1 core, and suggest that virion-associated Nef may facilitate an early step in HIV- 1 infection following dissociation of the viral capsid in the target cell.

Nef Can Enhance the Infectivity of Receptor-Pseudotyped Human Immunodeficiency Virus Type 1 Particles

TLDR
The results demonstrate that the presence of a viral Env protein during virus production is not required for the ability of Nef to increase viral infectivity, and concludes that low-pH-dependent entry does not always bypass the requirement for Nef.
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