The solution structure of the bovine leukaemia virus matrix protein and similarity with lentiviral matrix proteins.

Matthews, S J; Mikhailov, Michael; Burny, Arsène; Roy, Polly

doi:10.1002/j.1460-2075.1996.tb00691.x

Cited by 37 publications

(36 citation statements)

References 35 publications

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“…On the other hand, we do find it compelling that there is remarkable similarity in the three-dimensional structures of all retroviral MA proteins, each having four major alpha helices separated by flexible loops, with the first two helices overlapping the second two (14,28,38,39). The structures of these evolutionarily diverse MA proteins are conserved even though the mechanisms that they use for membrane binding are not (e.g., the requirements for myristate and the clustering of basic residues differ for RSV and HIV) (55,63).…”

Section: Discussionmentioning

confidence: 72%

RNA Dimerization Defect in a Rous Sarcoma Virus Matrix Mutant

Parent

Cairns

Albert³

et al. 2000

J Virol

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The retrovirus matrix (MA) sequence of the Gag polyprotein has been shown to contain functions required for membrane targeting and binding during particle assembly and budding. Additional functions for MA have been proposed based on the existence of MA mutants in Rous sarcoma virus (RSV), murine leukemia virus, human immunodeficiency virus type 1, and human T-cell leukemia virus type 1 that lack infectivity even though they release particles of normal composition. Here we describe an RSV MA mutant with a surprising and previously unreported phenotype. In the mutant known as Myr1E, the small membrane-binding domain of the Src oncoprotein has been added as an N-terminal extension of Gag. While Myr1E is not infectious, full infectivity can be reestablished by a single amino acid substitution in the Src sequence (G2E), which eliminates the addition of myristic acid and the membrane-binding capacity of this foreign sequence. The presence of myristic acid at the N terminus of the Myr1E Gag protein does not explain its replication defect, because other myristylated derivatives of RSV Gag are fully infectious (e.g., Myr2 [C. R. Erdie and J. W. Wills, J. Virol. 64:5204-5208, 1990]). Biochemical analyses of Myr1E particles reveal that they contain wild-type levels of the Gag cleavage products, Env glycoproteins, and reverse transcriptase activity when measured on an exogenous template. Genomic RNA incorporation appears to be mildly reduced compared to the wild-type level. Unexpectedly, RNA isolated from Myr1E particles is monomeric when analyzed on nondenaturing Northern blots. Importantly, the insertional mutation does not lie within previously identified dimer linkage sites. In spite of the dimerization defect, the genomic RNA from Myr1E particles serves efficiently as a template for reverse transcription as measured by an endogenous reverse transcriptase assay. In marked contrast, after infection of avian cells, the products of reverse transcription are nearly undetectable. These findings might be explained either by the loss of a normal function of MA needed in the formation or stabilization of RNA dimers or by the interference in such events by the mutant MA molecules. It is possible that Myr1E viruses package a single copy of viral RNA.The retrovirus Gag polyprotein directs the assembly and budding of virus particles from the plasma membrane of infected cells. Extensive functional mapping of several Gag proteins has led to the identification of three common assembly domains that are required for this activity. The N-terminal membrane-binding (M) domain directs Gag molecules from the cytoplasm to the inner leaflet of the plasma membrane (44,55,63) where aggregates of Gag proteins are formed through protein-protein interactions primarily involving the I (interaction) domains (4, 12, 22, 57). These interactions lead to the emergence of spherical particles that pinch off the membrane during the final step in the budding process, which is mediated by the L (late) assembly domain (27,45,58). Virus maturation occurs as the...

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Section: Discussionmentioning

confidence: 72%

RNA Dimerization Defect in a Rous Sarcoma Virus Matrix Mutant

Parent

Cairns

Albert³

et al. 2000

J Virol

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“…It may be relevant in this regard that FIV has the shortest Env CT among the lentiviruses (4,41). By contrast, when considering retroviruses outside the lentiviruses, none of the MA structures available for human T-cell leukemia virus (HTLV) II (42), bovine leukemia virus (BLV) (43), Moloney murine leukemia virus (Mo-MLV) (38), Rous sarcoma virus (RSV) (44), or M-PMV (45) revealed an MA trimer, although, in every case except RSV, the authors felt that a trimeric MA was possible, based primarily on their close structural conservation with HIV-1 and SIV MA. It has been suggested that the formation of MA trimers is a precursor to Gag assembly in BLV and M-PMV (43, 45); however, our data suggest that in the case of HIV-1, loss of MA trimerization does not significantly impact viruslike particle assembly and therefore does not play a major role in Gag lattice formation.…”

Section: Discussionmentioning

confidence: 99%

Biochemical evidence of a role for matrix trimerization in HIV-1 envelope glycoprotein incorporation

Tedbury

Novikova

Ablan

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

122

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The matrix (MA) domain of HIV Gag has important functions in directing the trafficking of Gag to sites of assembly and mediating the incorporation of the envelope glycoprotein (Env) into assembling particles. HIV-1 MA has been shown to form trimers in vitro; however, neither the presence nor the role of MA trimers has been documented in HIV-1 virions. We developed a cross-linking strategy to reveal MA trimers in virions of replication-competent HIV-1. By mutagenesis of trimer interface residues, we demonstrated a correlation between loss of MA trimerization and loss of Env incorporation. Additionally, we found that truncating the long cytoplasmic tail of Env restores incorporation of Env into MA trimer-defective particles, thus rescuing infectivity. We therefore propose a model whereby MA trimerization is required to form a lattice capable of accommodating the long cytoplasmic tail of HIV-1 Env; in the absence of MA trimerization, Env is sterically excluded from the assembling particle. These findings establish MA trimerization as an obligatory step in the assembly of infectious HIV-1 virions. As such, the MA trimer interface may represent a novel drug target for the development of antiretrovirals.HIV | retrovirus | matrix | envelope | trimerization

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“…Similar residues in the HIV-1 NC zinc finger have been implicated in interactions with SL3 RNA and have been shown to be important for RNA packaging by mutagenesis studies (9). The basic residues in the BLV MA that caused the greatest defects in RNA packaging (i.e., K41 and H45) are located in ␣-helix B (28). Presently, no structural data are available regarding the potential viral RNA-MA protein interactions.…”

Section: Discussionmentioning

confidence: 99%

Involvement of the Matrix and Nucleocapsid Domains of the Bovine Leukemia Virus Gag Polyprotein Precursor in Viral RNA Packaging

Wang

Norris

Mansky

2003

J Virol

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The RNA packaging process for retroviruses involves a recognition event of the genome-length viral RNA by the viral Gag polyprotein precursor (PrGag), an important step in particle morphogenesis. The mechanism underlying this genome recognition event for most retroviruses is thought to involve an interaction between the nucleocapsid (NC) domain of PrGag and stable RNA secondary structures that form the RNA packaging signal. Presently, there is limited information regarding PrGag-RNA interactions involved in RNA packaging for the deltaretroviruses, which include bovine leukemia virus (BLV) and human T-cell leukemia virus types 1 and 2 (HTLV-1 and -2, respectively). To address this, alanine-scanning mutagenesis of BLV PrGag was done with a virus-like particle (VLP) system. As predicted, mutagenesis of conserved basic residues as well as residues of the zinc finger domains in the BLV NC domain of PrGag revealed residues that led to a reduction in viral RNA packaging. Interestingly, when conserved basic residues in the BLV MA domain of PrGag were mutated to alanine or glycine, but not when mutated to another basic residue, reductions in viral RNA packaging were also observed. The ability of PrGag to be targeted to the cell membrane was not affected by these mutations in MA, indicating that PrGag membrane targeting was not associated with the reduction in RNA packaging. These observations indicate that these basic residues in the MA domain of PrGag influence RNA packaging, without influencing Gag membrane localization. It was further observed that (i) a MA/NC double mutant had a more severe RNA packaging defect than either mutant alone, and (ii) RNA packaging was not found to be associated with transient localization of Gag in the nucleus. In summary, this report provides the first direct evidence for the involvement of both the BLV MA and NC domains of PrGag in viral RNA packaging.The RNA packaging process for retroviruses involves a recognition event of the genome-length viral RNA by the viral Gag polyprotein precursor (PrGag), which acts to initiate the morphogenesis of virus particles (see reference 17 for review). The mechanism underlying this genome recognition event is poorly understood, but many biochemical and genetic analyses have revealed that this event involves the interaction between stable RNA secondary structures at the 5Ј end of the viral genome and, in many cases, amino acids in the nucleocapsid (NC) domain of PrGag (1,2,4,6,7,9,10,13,15,29,30,32,36,37).The genome recognition event is an important step in the morphogenesis of infectious retrovirus particles. This recognition event leads to the predominant packaging (encapsidation) of the genome-length viral RNA into assembling particles (38). This discrimination process, which is primarily a viral RNAprotein interaction, is known to strongly favor the full-length viral RNA over spliced viral RNAs and cellular mRNAs (38). In general, the RNA sequences necessary and sufficient for the RNA packaging process are located in a region that includes the 5Ј-...

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The solution structure of the bovine leukaemia virus matrix protein and similarity with lentiviral matrix proteins.

Cited by 37 publications

References 35 publications

RNA Dimerization Defect in a Rous Sarcoma Virus Matrix Mutant

RNA Dimerization Defect in a Rous Sarcoma Virus Matrix Mutant

Biochemical evidence of a role for matrix trimerization in HIV-1 envelope glycoprotein incorporation

Involvement of the Matrix and Nucleocapsid Domains of the Bovine Leukemia Virus Gag Polyprotein Precursor in Viral RNA Packaging

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