Mutational analysis of the N-linked glycosylation sites of the SU envelope protein of Moloney murine leukemia virus

Felkner, Roland H.; Roth, Monica J.

doi:10.1128/jvi.66.7.4258-4264.1992

Cited by 56 publications

(42 citation statements)

References 43 publications

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“…A similar phenotype was observed for the MPMV envelope containing a 35-amino-acid deletion in the extracellular domain of TM (3). Similar results have also been observed in other retroviral systems due to changes in SU, not TM (19,33,36,52). Analysis of these mutant precursors suggests that when the block in the envelope processing pathway occurs in the endoplasmic reticulum, the precursor is not transported to the cell surface.…”

Section: Discussionsupporting

confidence: 79%

Mutations within a putative cysteine loop of the transmembrane protein of an attenuated immunodeficiency-inducing feline leukemia virus variant inhibit envelope protein processing

Burns

Poss

Thomas

et al. 1995

J Virol

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A replication-defective feline leukemia virus molecular clone, 61B, has been shown to cause immunodeficiency in cats and cytopathicity in T cells after a long latency period when coinfected with a minimally pathogenic helper virus (J. Overbaugh, E. A. Hoover, J. I. Mullins, D. P. W. Burns, L. Rudensey, S. L. Quackenbush, V. Stallard, and P. R. Donahue, Virology 188:558-569, 1992). The long-latency phenotype of 61B has been mapped to four mutations in the extracellular domain of the envelope transmembrane protein, and we report here that these mutations cause a defect in envelope protein processing. Immunoprecipitation analyses demonstrated that the 61B gp85 envelope precursor was produced but that further processing to generate the surface protein (SU/gp70) and the transmembrane protein (TM/p15E) did not occur. The 61B precursor was not expressed on the cell surface and appeared to be retained in the endoplasmic reticulum or Golgi apparatus. Two of the four 61B-specific amino acid changes are located within a putative cysteine loop in a region of TM that is conserved among retroviruses. Introduction of these two amino acid changes into a replication-competent highly cytopathic virus resulted in the production of noninfectious virus that exhibited an envelope-protein-processing defect. This analysis suggests that mutations in a conserved region within a putative cysteine loop affect retroviral envelope protein maturation and viral infectivity.

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Section: Discussionsupporting

confidence: 79%

Mutations within a putative cysteine loop of the transmembrane protein of an attenuated immunodeficiency-inducing feline leukemia virus variant inhibit envelope protein processing

Burns

Poss

Thomas

et al. 1995

J Virol

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“…The replication-competent M-MLV proviral construct pNCA-C [84] and pNCA-C IN-XN (previously named in6215a [40]), bearing a 23-aa truncation of the IN tail peptide (TP) of the C-terminal domain (CTD) was previously described [40]. To generate a codon-optimized pNCA-C-TP -, a 137 bp gene block (IDT) was chemically synthesized and amplified using primers NCACXN_ScaI6330_rev and NCACXN_NotI6220_fwd.…”

Section: Plasmid and Vector Constructionmentioning

confidence: 99%

Disrupting MLV integrase:BET protein interaction biases integration into quiescent chromatin and delays but does not eliminate tumor activation in a MYC/Runx2 mouse model

et al. 2019

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Murine leukemia virus (MLV) integrase (IN) lacking the C-terminal tail peptide (TP) loses its interaction with the host bromodomain and extraterminal (BET) proteins and displays decreased integration at promoter/enhancers and transcriptional start sites/CpG islands. MLV lacking the IN TP via an altered open reading frame was used to infect tumorigenesis mouse model (MYC/Runx2) animals to observe integration patterns and phenotypic effects, but viral passage resulted in the restoration of the IN TP through small deletions. Mice subsequently infected with an MLV IN lacking the TP coding sequence (TP -) showed an improved median survival by 15 days compared to wild type (WT) MLV infection. Recombination with polytropic endogenous retrovirus (ERV), Pmv20, was identified in seven mice displaying both fast and slow tumorigenesis, highlighting the strong selection within the mouse to maintain the full-length IN protein. Mapping the genomic locations of MLV in tumors from an infected mouse with no observed recombination with ERVs, TP -16, showed fewer integrations at TSS and CpG islands, compared to integrations observed in WT tumors. However, this mouse succumbed to the tumor in relatively rapid fashion (34 days). Analysis of the top copy number integrants in the TP -16 tumor revealed their proximity to known MLV common insertion site genes while maintaining the MLV IN TPgenotype. Furthermore, integration mapping in K562 cells revealed an insertion preference of MLV IN TPwithin chromatin profile states associated with weakly transcribed heterochromatin with PLOS Pathogens | https://doi.fewer integrations at histone marks associated with BET proteins (H3K4me1/2/3, and H3K27Ac). While MLV IN TPshowed a decreased overall rate of tumorigenesis compared to WT virus in the MYC/Runx2 model, MLV integration still occurred at regions associated with oncogenic driver genes independently from the influence of BET proteins, either stochastically or through trans-complementation by functional endogenous Gag-Pol protein. Author summaryMany different retroviruses, including murine leukemia virus (MLV), are used as vectors for human gene therapy and cancer immunotherapies (CAR-T) because of their stable and efficient delivery of genetic material into the host DNA. However, this process can result in activation and/or disruption of cellular genes, which has resulted in the outgrowth of tumors in previous clinical trials. Of critical importance is the preferred location within the host genome at which the retrovirus integrates. Our study presents a modified MLV virus that has lost the ability to bind to the host BET proteins, the drivers of insertion at promoter/enhancer regions of highly activated genes. This is the first direct study within an animal model to examine whether infection with this type of modified MLV virus affects tumor progression. We found that the modified virus improved the survival of the well-characterized MYC/Runx2 mouse compared to infections with the wild-type MLV. Most modified viral integrants mapped into less...

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“…The pNL4.3-ΔEnv, pNL4.3R, pNL4.3R-ΔRev, pROD10R and pNCAC proviral vectors were previously described (18,29,30). The pcDNA3-Flag-CTIF, pcDNA3-Flag-CTIF(1-305) and pcDNA3-Flag-CTIF(306-598) were previously described (25).…”

Section: Methodsmentioning

confidence: 99%

CBP80/20-dependent translation initiation factor (CTIF) inhibits HIV-1 Gag synthesis by targeting the function of the viral protein Rev

García-de-Gracia

Toro-Ascuy

Riquelme-Barrios

et al. 2019

Preprint

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1Translation initiation of the human immunodeficiency virus type-1 (HIV-1) unspliced mRNA 2 has been shown to occur through cap-dependent and IRES-driven mechanisms. Previous studies 3 suggested that the nuclear cap-binding complex (CBC) rather than eIF4E drives cap-dependent 4 translation of the unspliced mRNA and we have recently reported that the CBC subunit CBP80 5 supports the function of the viral protein Rev during nuclear export and translation of this viral 6 transcript. Ribosome recruitment during CBC-dependent translation of cellular mRNAs relies on 7 the activity CBP80/20 translation initiation factor (CTIF), which bridges CBP80 and the 40S 8 ribosomal subunit through interactions with eIF3g. Here, we report that CTIF restricts HIV-1 9 replication by interfering with Gag synthesis from the unspliced mRNA. Our results indicate that 10 CTIF associates with Rev through its N-terminal domain and is recruited onto the unspliced 11 mRNA ribonucleoprotein complex in order to block translation. We also demonstrate that CTIF 12 induces the cytoplasmic accumulation of Rev impeding the association of the viral protein with 13 CBP80. We finally show that CTIF restricts HIV-2 but not MLV Gag synthesis indicating an 14 inhibitory mechanism conserved in Rev-expressing human lentiviruses. 15 16 17 18 19 20

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Mutational analysis of the N-linked glycosylation sites of the SU envelope protein of Moloney murine leukemia virus

Cited by 56 publications

References 43 publications

Mutations within a putative cysteine loop of the transmembrane protein of an attenuated immunodeficiency-inducing feline leukemia virus variant inhibit envelope protein processing

Mutations within a putative cysteine loop of the transmembrane protein of an attenuated immunodeficiency-inducing feline leukemia virus variant inhibit envelope protein processing

Disrupting MLV integrase:BET protein interaction biases integration into quiescent chromatin and delays but does not eliminate tumor activation in a MYC/Runx2 mouse model

CBP80/20-dependent translation initiation factor (CTIF) inhibits HIV-1 Gag synthesis by targeting the function of the viral protein Rev

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