Effect of mutations affecting the p6 gag protein on human immunodeficiency virus particle release.

Abstract

Mutations in sequences at the C terminus of the capsid precursor protein of human immunodeficiency virus type 1 that affect the viral p6 protein prevent release of budded virus particles from the cell surface. The experiments reported here define an important step in the life cycle of the virus, the release of the budded particle from a tether that binds the assembled particle to the cell surface. Inhibition of the release of the viral capsid proteins by interferon a indicates that this step of virus maturation may be sensitive to inhibition by antiviral drugs.

HIV-1 Vpr-chloramphenicol acetyltransferase fusion proteins: sequence requirement for virion incorporation and analysis of antiviral effect

“…The faster migration of the pr55 gag polyprotein precursor encoded by the HxBRUR − /p6 − provirus reflects the C-terminal deletion of p6. 32 Even though similar amounts of each Vpr-CAT fusion protein were detected in both HxBRUR − and HxBRUR − /p6 − cotransfected cells (Figure 3a whereas virion incorporation of R1-42CAT and CATR3-42 occurs even in the absence of p6.…”

“…12 HxBRUR − /p6 − was constructed by replacing an ApaI-BclI (nt 1556-2011, +1 = start of initiation of transcription of HxBRU) fragment of HxBRUR − with a corresponding fragment from HxBc2/p6 − (S17/s), in which the codon specifying for serine residue 17 in the p6 domain of HIV Gag was changed to a stop codon TGA, as described previously. 32 The protease-defective HIV provirus SVC-p2 was a gift from Dr Gö ttlinger. 34 The wild-type Vpr expressor SVCMVVPR + and the negative control plasmid SVCMVVPR − that encodes a non-functional Vpr gene (initiation codon ATG-mutant), were previously described.…”

Gag-Gag interactions in the C-terminal domain of human immunodeficiency virus type 1 p24 capsid antigen are essential for Gag particle assembly

“…Recent evidence has located a discrete assembly signal in the MA domain (Freed et al, 1994;Chazal et al, 1995) and has also defined the functional basis of failure to assemble particles as an inability of Gag molecules to oligomerize (Morikawa et al, 1995). The majority of the NC domain appears not to be involved in Gag particle assembly although a role for a short SP1 peptide sequence at the CA/NC junction has been reported (Jowett et al, 1992;Hoshikawa et al, 1991 ;Pettit et al, 1994;Chazal et al, 1995;Krausslich et al, 1995), and the C-terminal protein p6 has an auxiliary role in efficient particle release from the cell and in recruiting Vpr into the budding virion (Paxton et al, 1993;Gottlinger et al, 1991). That sequences in the CA domain are essential for assembly was first indicated by the observations that Gag molecules with deletions in CA are defective in assembly and exhibit trans-dominance in complementation experiments (Trono et al, 1989).…”

In vitro selection of RNAs that bind to the human immunodeficiency virus type-1 gag polyprotein

“…Matrix also multimerizes to form the viral core, is required for incorporation of envelope proteins into assembling viruses (7), and plays a role in the entry of viral DNA into the nucleus prior to integration (8). The p6 protein plays a role in budding of viruses from cells (9) and binds to the HIV-1 vpr protein leading to its incorporation into viruses. The p1 and p2 peptides have been proposed to regulate the proteolysis of gag (11).…”