Expression and maturation of human foamy virus Gag precursor polypeptides

Giron, Marie-Lou; Colas, Sandrine; Wybier, Janine; Rozain, Francis; Emanoil-Ravier, Rodica

doi:10.1128/jvi.71.2.1635-1639.1997

Cited by 36 publications

(25 citation statements)

References 37 publications

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“…p70 is a cleavage product of the p74 precursor (pr74) (21). It has been suggested that p70 is cleaved from the amino terminus of pr74; however, ultimate proof for this assumption is lacking (12,21,22,25,37). We therefore constructed a set of HFV mutants, FIG.…”

Section: Resultsmentioning

confidence: 99%

“…With respect to the FV Gag protein, it has long been noted that two Gag proteins with apparent molecular masses of 70 and 74 kDa predominate in virion preparations and in virusinfected cells (17,25,26). Smaller Gag proteins, which may represent the MA, CA, and NC domains, have only occasionally been detected (12,17,25). The significance of the p70/p74 cleavage for virus replication has not been analyzed.…”

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confidence: 99%

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Carboxy-terminal cleavage of the human foamy virus Gag precursor molecule is an essential step in the viral life cycle

Enssle

Fischer

Moebes

et al. 1997

J Virol

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Foamy viruses (FVs) express the Gag protein as a precursor with a molecular mass of 74 kDa (pr74) from which a 70-kDa protein (p70) is cleaved by the viral protease. To gain a better understanding of FV Gag protein processing and function, we have generated and analyzed mutants in the C-terminal gag region of an infectious molecular clone. Our results show that p70 is an N-terminal cleavage product of pr74. However, we were unable to identify a p4 molecule. A virus mutant expressing p70 only was found to be replication competent, albeit at very low titers compared to those of wild-type virus. A strong tendency to synthesize and cleave a pr74 molecule was deduced from the occurrence of revertants upon transfection of this mutant. Substitution of the p6 gag domain of human immunodeficiency virus type 1 for the p4 domain of FV resulted in a stable chimeric virus which replicated to titers 10 times lower than those of wild-type virus. FV Gag protein was found to be phosphorylated at serine residues. Mutagenesis of serines conserved in the p4 domain had no influence on viral replication in cell culture. The p70/p74 Gag cleavage was found to be required for viral infectivity, since mutagenesis of the putative cleavage site led to replication-incompetent virus. Interestingly, the cleavage site mutants were defective in the intracellular cDNA synthesis of virion DNA, which indicates that correct FV particle formation and the generation of virion DNA are functionally linked.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Carboxy-terminal cleavage of the human foamy virus Gag precursor molecule is an essential step in the viral life cycle

Enssle

Fischer

Moebes

et al. 1997

J Virol

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“…Although FV Gag proteins participate to early and late stages of viral replication, they present distinct features that set them apart from other retroviral Gags. In particular, FV Gag proteins are mainly present in viral particles as precursors, a consequence of their inefficient cleavage by the viral protease during or following budding (22). Another unusual feature is the requirement of the homologous envelope (Env) glycoprotein for budding.…”

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confidence: 99%

Chromatin Tethering of Incoming Foamy Virus by the Structural Gag Protein

Tobaly-Tapiero

Bittoun

Lehmann-Che

et al. 2008

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Retroviruses hijack cellular machineries to productively infect their hosts. During the early stages of viral replication, proviral integration relies on specific interactions between components of the preintegration complex and host chromatin-bound proteins. Here, analyzing the fate of incoming primate foamy virus, we identify a short domain within the C-terminus of the structural Gag protein that efficiently binds host chromosomes, by interacting with H2A/H2B core histones. While viral particle production, virus entry and intracellular trafficking are not affected by mutation of this domain, chromosomal attachment of incoming subviral complexes is abolished, precluding proviral integration. We thus highlight a new function of the structural foamy Gag protein as the main tether between incoming subviral complexes and host chromatin prior to integration.

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“…The protein products of the primate foamy viruses and BFV have not been extensively characterized from cells or virus particles. We have identified the domains of Gag that likely encompass the mature MA, CA, and NC of BFV, based on analogy with data in reports describing HFV proteins (3,10,30). One clearly conserved region within the BFV gag gene encodes the GR boxes of the putative NC protein.…”

Section: Discussionmentioning

confidence: 95%

The Nucleotide Sequence and Spliced pol mRNA Levels of the Nonprimate Spumavirus Bovine Foamy Virus

Holzschu

Delaney

Renshaw

et al. 1998

J Virol

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We have determined the complete nucleotide sequence of a replication-competent clone of bovine foamy virus (BFV) and have quantitated the amount of splice pol mRNA processed early in infection. The 544-amino-acid Gag protein precursor has little sequence similarity with its primate foamy virus homologs, but the putative nucleocapsid (NC) protein, like the primate NCs, contains the three glycine-arginine-rich regions that are postulated to bind genomic RNA during virion assembly. The BFV gag and polopen reading frames overlap, with pro and polin the same translational frame. As with the human foamy virus (HFV) and feline foamy virus, we have detected a spliced pol mRNA by PCR. Quantitatively, this mRNA approximates the level of full-length genomic RNA early in infection. The integrase (IN) domain of reverse transcriptase does not contain the canonical HH-CC zinc finger motif present in all characterized retroviral INs, but it does contain a nearby histidine residue that could conceivably participate as a member of the zinc finger. The env gene encodes a protein that is over 40% identical in sequence to the HFV Env. By comparison, the Gag precursor of BFV is predicted to be only 28% identical to the HFV protein.

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Expression and maturation of human foamy virus Gag precursor polypeptides

Cited by 36 publications

References 37 publications

Carboxy-terminal cleavage of the human foamy virus Gag precursor molecule is an essential step in the viral life cycle

Carboxy-terminal cleavage of the human foamy virus Gag precursor molecule is an essential step in the viral life cycle

Chromatin Tethering of Incoming Foamy Virus by the Structural Gag Protein

The Nucleotide Sequence and Spliced pol mRNA Levels of the Nonprimate Spumavirus Bovine Foamy Virus

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