Mutational Analysis of the Putative Receptor-Binding Domain of Moloney Murine Leukemia Virus Glycoprotein gp70

Panda, Binaya R.; Kingsman, Susan M.; Kingsman, Alan J.

doi:10.1006/viro.2000.0397

Cited by 9 publications

(13 citation statements)

References 23 publications

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“…Interaction between RBD and the ecotropic receptor murine cationic amino acid transporter 1 (mCAT-1) is essential for MLV membrane fusion and entry and for syncytium formation (1,22,53). Previous studies assessed the impact of multiple amino acid changes in Env on expression, binding, and viral entry in MLV with related genetic backgrounds (11,33). These studies showed that nonconservative substitutions of glycine or threonine for tryptophan at Env 102 altered receptor binding and transduction efficiency.…”

Section: Tr13 Is a Friend Murine Leukemia Virus (Mlv) That Induces Smentioning

confidence: 99%

“…Correct orientation was confirmed by diagnostic restriction enzyme digestions. Pseudotyped viruses were generated by triple transfection as described previously (2,33). For viral interference assays, 10 5 cells were plated and infected overnight with pseudotyped viruses at an MOI of 5 in 8-g/ml Polybrene.…”

Section: Cellsmentioning

confidence: 99%

mentioning

confidence: 97%

“…These studies showed that nonconservative substitutions of glycine or threonine for tryptophan at Env 102 altered receptor binding and transduction efficiency. However, unlike with TR1.3 and W102G, Env substitutions on these backgrounds did not result in the SI phenotype (11,33).Following MLV infection, Env downmodulates the level of available receptor on the cell surface (16,31). This process, known as superinfection interference, prevents a virally infected cell from undergoing additional rounds of infection by the same or related viruses that utilize the same cellular receptor (44,50,55).…”

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Linkage of Reduced Receptor Affinity and Superinfection to Pathogenesis ofTR1.3 Murine Leukemia Virus

Murphy

Chung-Landers

Honczarenko

et al. 2006

J Virol

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TR1.3 is a Friend murine leukemia virus (MLV) that induces selective syncytium induction (SI) of brain capillary endothelial cells (BCEC),The ecotropic Friend murine leukemia virus (MLV) TR1.3 was previously defined as an acutely cytopathic, syncytiuminducing (SI) variant of the noncytopathic, non-syncytium-inducing (NSI) MLV FB29. When inoculated into neonatal BALB/c mice, TR1.3 infected and caused syncytium formation in brain capillary endothelial cells (34-36). These cytopathic effects paralleled a breakdown of the blood brain barrier and hemorrhagic stroke formation. The molecular basis of both the SI phenotype and in vivo neurologic disease was previously mapped to a tryptophan (W)-to-glycine (G) substitution at amino acid position Env 102 (37). Introduction of the W102G substitution into the NSI FB29 molecular clone yielded an SI pathogenic phenotype that was identical to that seen with TR1.3. The mechanism(s) whereby mutations at Env 102 mediate SI and disease is unknown.The MLV Env consists of surface and transmembrane subdomains. Amino acids 1 to 236 of SU encompass the putative receptor binding domain (RBD) (10). Analysis of the RBD crystal structure indicates that amino acid 102 lies at the base of the predicted receptor binding pocket (13). Interaction between RBD and the ecotropic receptor murine cationic amino acid transporter 1 (mCAT-1) is essential for MLV membrane fusion and entry and for syncytium formation (1,22,53). Previous studies assessed the impact of multiple amino acid changes in Env on expression, binding, and viral entry in MLV with related genetic backgrounds (11,33). These studies showed that nonconservative substitutions of glycine or threonine for tryptophan at Env 102 altered receptor binding and transduction efficiency. However, unlike with TR1.3 and W102G, Env substitutions on these backgrounds did not result in the SI phenotype (11,33).Following MLV infection, Env downmodulates the level of available receptor on the cell surface (16,31). This process, known as superinfection interference, prevents a virally infected cell from undergoing additional rounds of infection by the same or related viruses that utilize the same cellular receptor (44,50,55). In rare circumstances, failure of MLV Env to establish superinfection interference is linked to either low Env expression levels and/or diminished mCAT-1 binding (3,4,49).Important pathological consequences can result from retroviral superinfection. Superinfection can lead to the accumulation of unintegrated linear DNA in the cytoplasm (51); by virtue of the similarity between unintegrated viral DNA and damaged DNA, this may trigger apoptosis induction in superinfected cells (9, 51). Failure to block superinfection has been linked to the in vivo cytotoxicity of mink cell focus-forming virus M13 and the neuropathogenic MLV Moloney ts1 (51, 56).Murine leukemia viruses are facile tools for investigating the mechanisms of retroviral pathogenesis (26). Several correlates of increased fusion activity have been attributed to Env including ...

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Section: Tr13 Is a Friend Murine Leukemia Virus (Mlv) That Induces Smentioning

confidence: 99%

Section: Cellsmentioning

confidence: 99%

mentioning

confidence: 97%

mentioning

confidence: 99%

See 2 more Smart Citations

Linkage of Reduced Receptor Affinity and Superinfection to Pathogenesis ofTR1.3 Murine Leukemia Virus

Murphy

Chung-Landers

Honczarenko

et al. 2006

J Virol

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“…These studies have been further refined by analyzing mutants with subtler alterations, such as single residue substitutions or small insertions (2,9,11,20,45). However, the ability to ascribe function to particular features of Env has been limited by the relatively small number of mutations analyzed in comparison to the large size of the protein.…”

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confidence: 99%

Comprehensive Mutational Analysis of the Moloney Murine Leukemia Virus Envelope Protein

Rothenberg¹,

Olsen

Laurent

et al. 2001

J Virol

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The envelope (Env) protein of Moloney murine leukemia virus is the primary mediator of viral entry. We constructed a large pool of insertion mutations in the env gene and analyzed the fitness of each mutant in completing two critical steps in the virus life cycle: (i) the expression and delivery of the Env protein to the cell surface during virion assembly and (ii) the infectivity of virions displaying the mutant proteins. The majority of the mutants were poorly expressed at the producer cell surface, suggesting folding defects due to the presence of the inserted residues. The mutants with residual infectivity had insertions either in the aminoterminal signal sequence region, two disulfide-bonded loops in the receptor binding domain, discrete regions of the carboxy-terminal region of the surface subunit (SU), or the cytoplasmic tail. Insertions that allowed the mutants to reach the cell surface but not to mediate detectable infection were located within the aminoterminal sequence of the mature Env, within the SU carboxy-terminal region, near putative receptor binding residues, and throughout the fusion peptide. Independent analysis of select mutants in this group allowed more precise identification of the defect in Env function. Mapping of mutant phenotypes to a structural model of the receptor-binding domain provides insights into the protein's functional organization. The high-resolution functional map reported here will be valuable for the engineering of the Env protein for a variety of uses, including gene therapy.Cell entry by retroviruses is mediated by the virally encoded Env glycoprotein on the virus surface. The Env protein of Moloney murine leukemia virus (MoMLV), the best-characterized mammalian type C retrovirus, is synthesized as a single 85-kDa precursor that includes an amino-terminal signal sequence that directs its insertion into the lumen of the endoplasmic reticulum (ER) (61). During transport to the cell surface, the Env precursor undergoes a series of posttranslational modifications, including glycosylation, oligomerization, disulfide bond formation and cleavage into surface (SU) and transmembrane (TM) subunits (19,46,47,48). At the cell surface, the Env trimer is incorporated into the membrane of the budding virion, where it is further modified by the virally encoded protease, which removes the carboxy-terminal 16 amino acids (the R-peptide) of TM to yield the entry-competent glycoprotein (22, 50, 51, 52).The entry process is initiated by the specific interaction of the Env protein with the receptor protein MCAT-1, which is located on the surface of a susceptible cell (1). Receptorbound virion particles are then internalized, probably by clathrin-independent endocytosis (38). By analogy with the influenza hemagglutinin (HA) fusion protein, the reduced pH within the endosome mediates a conformational change in the Moloney Env protein that exposes the fusion peptide at the amino terminus of TM (55). Fusion, initiated by the insertion of the fusion peptide into the endosomal membrane, permits ...

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Retroviral particles are effectively purified on an affinity matrix containing peptides selected by phage‐display

Fernandes

Barbosa

Pina

et al. 2016

Biotechnology Journal

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Retroviral particles are expensive to manufacture, mostly due to the downstream processing steps which result in low recoveries (≈30%) and concentration factors. In this work, a dodecapeptide phage-display library was panned against retrovirus like particles expressing the envelope protein Ampho4070A (VLPs-AMPHO) and VLPs without the target protein, used as a negative control (VLPs). A depletion/selection panning protocol was successfully used to deal with the structural complexity of the target, and a total of three distinct peptide sequences displaying preferential binding towards VLPs-AMPHO were found. Peptide 3 (CAAALAKPHTENHLLT), which appeared as one lead candidate, was synthesized and immobilized onto two purification matrices, cross-linked agarose and magnetic particles. The matrices selectively bound VLPs-AMPHO and in both cases recovery yields higher than 90% were obtained when employing mild elution conditions, while maintaining viral particle morphology and size.

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Mutational Analysis of the Putative Receptor-Binding Domain of Moloney Murine Leukemia Virus Glycoprotein gp70

Cited by 9 publications

References 23 publications

Linkage of Reduced Receptor Affinity and Superinfection to Pathogenesis ofTR1.3 Murine Leukemia Virus

Linkage of Reduced Receptor Affinity and Superinfection to Pathogenesis ofTR1.3 Murine Leukemia Virus

Comprehensive Mutational Analysis of the Moloney Murine Leukemia Virus Envelope Protein

Retroviral particles are effectively purified on an affinity matrix containing peptides selected by phage‐display

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