Use of a Transient Assay for Studying the Genetic Determinants of
            <i>Fv1</i>
            Restriction

Bock, Michael; Bishop, Kate N.; Towers, Greg J.; Stoye, Jonathan P.

doi:10.1128/jvi.74.16.7422-7430.2000

Cited by 125 publications

(157 citation statements)

References 22 publications

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“…The transduced cells were fully susceptible to NB-tropic Friend MLV (FBLV), but MDTF cells expressing Fv1 n showed reduced susceptibility to AKV-B, and cells expressing Fv1 m showed reduced susceptibility to both AKV-B and AKV-N. The fact that the transduced cells did not reproduce the level of restriction seen in M. n. minutoides or NIH 3T3 cells is consistent with previous observations that Fv1 is highly sensitive to concentration and that not all transfected cells show restriction (3,14). In 3 independent experiments, however, the transduced MDTF cells reproduced the distinctive restriction patterns of M. n. minutoides and NIH 3T3.…”

Section: Restriction Of Ecotropic Mlvs In Cells Of 2 Species Of Nannosupporting

confidence: 77%

Origin, antiviral function and evidence for positive selection of the gammaretrovirus restriction gene Fv1 in the genus Mus

Yan

Buckler-White

Wollenberg

et al. 2009

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

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The Fv1 virus resistance gene is a coopted endogenous retrovirus (ERV) sequence related to the gag gene of the MuERV-L ERV family. Three major Fv1 resistance alleles have been identified in laboratory mice, and they target virus capsid genes to produce characteristic patterns of resistance to mouse leukemia viruses (MLVs). We identified Fv1 in 3 of the 4 Mus subgenera; its absence from Coelomys and 1 of 3 species of Pyromys indicate Fv1 was acquired shortly after the origin of the Mus genus. We sequenced Fv1 genes from 21 mice representative of the major taxonomic groups of Mus . Two lines of evidence indicate that Fv1 has had antiviral function for 7 million years of evolution. First, 2 species of African pygmy mice (subgenus Nannomys ) show an Fv1 -like MLV resistance, and transduced cells expressing the Nannomys Fv1 gene reproduce this resistance pattern. Second, sequence comparisons suggest that Fv1 has been involved in genetic conflicts throughout Mus evolution. We found evidence for strong positive selection of Fv1 and identified 6 codons that show evidence of positive selection: 3 codons in the C-terminal region including 2 previously shown to contribute to Fv1 restriction in laboratory mice, and 3 codons in a 10-codon segment overlapping the major homology region of Fv1 ; this segment is known to be involved in capsid multimerization. This analysis suggests that Fv1 has had an antiviral role throughout Mus evolution predating exposure of mice to the MLVs restricted by laboratory mouse Fv1 , and suggests a mechanism for Fv1 restriction.

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Section: Restriction Of Ecotropic Mlvs In Cells Of 2 Species Of Nannosupporting

confidence: 77%

Origin, antiviral function and evidence for positive selection of the gammaretrovirus restriction gene Fv1 in the genus Mus

Yan

Buckler-White

Wollenberg

et al. 2009

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

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“…The N-MLV and B-tropic MLV (B-MLV) Gag proteins differ by a few amino acids, 49 and amino acid 110 in the capsid domain determines the sensitivity of MLV to TRIM5a hu and to Fv1, another restriction factor functionally (if not structurally) related to TRIM5a. 50,51 In our hands, N-MLV replication was decreased by overexpression of wild-type TRIM5a hu (Supplementary Figure 1).…”

Section: Restriction Of Other Retrovirusesmentioning

confidence: 99%

Generation of human TRIM5α mutants with high HIV-1 restriction activity

et al. 2010

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“…For gammaretrovirus production, the retroviral vector expression plasmid (5 g) was cotransfected with expression plasmids for Moloney-MLV gag-pol (M57DAW, 15 g) and either ecotropic (K73, 3 g; kindly provided by T. Kitamura, Tokio, Japan) or glycoprotein from vesicular stomatitis virus (VSVg) (pMD.G, 2 g) envelope. For the production of N-or B-tropic gammaretroviral particles, we used 5 g of either pCIG3N or pCIG3B gag-pol expression plasmid (4). To ensure equal transfection efficiencies of gammaretroviral nucleus-localizing Cre (nlsCre) vectors, 1 g of the pEGFP-C1 expression plasmid (BD Clontech, Heidelberg, Germany) was cotransfected.…”

Section: Methodsmentioning

confidence: 99%

Cellular Restriction of Retrovirus Particle-Mediated mRNA Transfer

Galla

Schambach

Towers³

et al. 2008

J Virol

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Analyzing cellular restriction mechanisms provides insight into viral replication strategies, identifies targets for antiviral drug design, and is crucial for the development of novel tools for experimental or therapeutic delivery of genetic information. We have previously shown that retroviral vector mutants that are unable to initiate reverse transcription mediate a transient expression of any sequence which replaces the gag-pol transcription unit, a process we call retrovirus particle-mediated mRNA transfer (RMT). Here, we further examined the mechanism of RMT by testing its sensitivity to cellular restriction factors and short hairpin RNAs (shRNAs). We found that both human TRIM5␣ and, to a lesser extent, Fv1 effectively restrict RMT if the RNA is delivered by a restriction-sensitive capsid. While TRIM5␣ restriction of RMT led to reduced levels of retroviral mRNA in target cells, restriction by Fv1 did not. Treatment with the proteasome inhibitor MG132 partially relieved TRIM5␣-mediated restriction of RMT. Finally, cells expressing shRNAs specifically targeting the retroviral mRNA inhibited RMT particles, but not reverse-transcribing particles. Retroviral mRNA may thus serve as a translation template if not used as a template for reverse transcription. Our data imply that retroviral nucleic acids become accessible to host factors, including ribosomes, as a result of particle remodeling during cytoplasmic trafficking.Retroviruses enter cells in a receptor-mediated manner, following which a reverse transcription (RT) complex is formed in the cytoplasm to reverse transcribe the genomic mRNA into double-stranded DNA. During the completion of RT, a hybrid virus-cellular nucleoprotein structure known as the preintegration complex (PIC) is formed. Eventually, active transport of the PIC into the nucleus or dissolution of the nuclear membrane during mitosis allows the viral integrase to integrate the viral double-stranded DNA into chromosomal cellular DNA (35). We have previously shown that retroviral vector mutants that are unable to initiate RT of their capped, plus-stranded mRNA genomes mediate a transient expression of the sequences cloned into the gag-pol-equivalent position of the vector genome (8). Particles conferring this activity required the presence of the retroviral mRNA packaging signal within the vector sequence, as well as the expression of both Gag and Env in the vector packaging cell, but not reverse transcriptase. We refer to this previously unexplored aspect of the retrovirus life cycle as retrovirus particle-mediated mRNA transfer (RMT). Using replication-defective retroviral vectors in which the gene of interest is cloned in the position of the gag reading frame, RMT can be exploited as a novel approach for the transient expression of a gene of interest (8).The analysis of cellular restriction factors that belong to the innate immune response against retroviruses may provide further insights into the mechanisms of RMT. The cellular restriction factor Fv1 (Friend virus susceptibility factor 1) h...

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Use of a Transient Assay for Studying the Genetic Determinants of Fv1 Restriction

Abstract: To probe the genetic determinants controlling the interaction between the retroviral restriction gene Fv1 and its murine leukemia virus target, we set out to develop rapid, transient assays for

Cited by 125 publications

References 22 publications

Origin, antiviral function and evidence for positive selection of the gammaretrovirus restriction gene Fv1 in the genus Mus

Origin, antiviral function and evidence for positive selection of the gammaretrovirus restriction gene Fv1 in the genus Mus

Generation of human TRIM5α mutants with high HIV-1 restriction activity

Cellular Restriction of Retrovirus Particle-Mediated mRNA Transfer

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