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. 1997 Feb;71(2):1013–1018. doi: 10.1128/jvi.71.2.1013-1018.1997

Nef association with human immunodeficiency virus type 1 virions and cleavage by the viral protease.

A A Bukovsky 1, T Dorfman 1, A Weimann 1, H G Göttlinger 1
PMCID: PMC191151  PMID: 8995620

Abstract

Nef is a regulatory gene product of human immunodeficiency virus type 1 (HIV-1) and other primate lentiviruses which enhances virion infectivity by an unknown mechanism. We report here that Nef is detectable at moderate levels in preparations of HIV-1 virions which lack active viral protease (PR). Significantly smaller amounts of intact Nef were present in wild-type virion preparations. Instead, a smaller Nef-related product with an apparent molecular mass of 18 kDa was associated with wild-type virions, indicating that packaging of Nef resulted in cleavage by the viral PR. The presence of the HIV-1 PR inhibitor A77003 during virus production prevented the appearance of the 18-kDa Nef product and caused an accumulation of full-length Nef in virion preparations. Nef associated with comparable efficiency with viral particles produced by the Gag polyproteins of HIV-1 and Moloney murine leukemia virus, indicating that no specific interaction with a virion component is required for the incorporation of Nef. The N-terminal 86 amino acids of Nef were sufficient for packaging into virions. A nonmyristylated form of Nef associated with viral particles with considerably lower efficiency, suggesting that Nef gains access into nascent virions primarily as a consequence of its affinity for membranes. Our results raise the possibility that Nef enhances infectivity directly as a component of the virion.

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Selected References

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