Receptor-binding properties of a purified fragment of the 4070A amphotropic murine leukemia virus envelope glycoprotein.

ABSTRACT Based on previous structural and functional studies, a potential receptor-binding site composed of residues that form a pocket at one end of the two long antiparallel helices in the receptor-binding domain of Friend 57 murine leukemia virus envelope protein (RBD) has been proposed. To test this hypothesis, directed substitutions for residues in the pocket were introduced and consequences for infection and for receptor binding were measured. Receptor binding was measured initially by a sensitive assay based on coexpression of receptor and RBD inXenopus oocytes, and the findings were confirmed by using purified proteins. Three residues that are critical for both binding and infection (S84, D86, and W102), with side chains that extend into the pocket, were identified. Moreover, when mCAT-1 was overexpressed, the infectivity of Fr57-MLV carrying pocket substitutions was partially restored. Substitutions for 18 adjacent residues and 11 other previously unexamined surface-exposed residues outside of the RBD pocket had no detectable effect on function. Taken together, these findings support a model in which the RBD pocket interacts directly with mCAT-1 (likely residues, Y235 and E237) and multiple receptor-envelope complexes are required to form the fusion pore.

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Definition of a 14-Amino-Acid Peptide Essential for the Interaction between the Murine Leukemia Virus Amphotropic Envelope Glycoprotein and Its Receptor

Journal of Virology ◽

10.1128/jvi.72.1.428-435.1998 ◽

1998 ◽

Vol 72 (1) ◽

pp. 428-435 ◽

Cited By ~ 23

Author(s):

Jean Luc Battini ◽

Olivier Danos ◽

Jean Michel Heard

Keyword(s):

Amino Acid ◽

Receptor Binding ◽

Envelope Glycoprotein ◽

Murine Leukemia Virus ◽

Leukemia Virus ◽

Target Cells ◽

Structural Constraints ◽

Binding Interaction ◽

Receptor Recognition ◽

Murine Leukemia

ABSTRACT Hydrophilic loops in the receptor binding domain of the amphotropic murine leukemia virus (MLV) envelope glycoprotein (SU) are predicted and may participate in SU-receptor interactions. We have replaced five segments of 6 to 15 amino acids located in each of these regions with an 11-amino-acid tag from the vesicular stomatitis virus glycoprotein (VSV-G). Substitution was compatible with envelope processing, transport, and incorporation into virions. However, three substitution mutants showed a temperature-dependent phenotype, suggesting structural unstability. Accessibility of the tagging epitope for a monoclonal anti-VSV-G antibody was greater in oligomeric than in monomeric SUs when insertion was done in VRA, a domain essential for receptor recognition. In contrast, accessibility was independent of structural constraints when insertion was done in VRB, a domain playing an accessory role in receptor binding. Interaction with the amphotropic receptor was investigated by interference assay and study of binding and infection of target cells with MLV particles coated with the substituted envelopes. Envelope-receptor interaction was abolished when substitution was performed in a potential loop-forming segment located at the N-terminal half of VRA. Although interaction was affected to variable extents, depending on the substituted segment, other mutants conserved the ability to interact with the amphotropic receptor. These experiments indicate the 14-amino-acid segment between positions 50 and 64 of SU as an essential determinant of amphotropic-receptor recognition. They also show that a foreign linear epitope can be tolerated in several locations of the amphotropic SU receptor binding site, and this result has implications for the design of targeted retroviral vectors.

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Small synthetic ligands for the enrichment of viral particles pseudotyped with amphotropic murine leukemia virus envelope

Journal of Chromatography A ◽

10.1016/j.chroma.2016.02.026 ◽

2016 ◽

Vol 1438 ◽

pp. 160-170 ◽

Cited By ~ 5

Author(s):

Cláudia S.M. Fernandes ◽

Rute Castro ◽

Ana Sofia Coroadinha ◽

A. Cecília A. Roque

Keyword(s):

Murine Leukemia Virus ◽

Leukemia Virus ◽

Virus Envelope ◽

Amphotropic Murine Leukemia Virus ◽

Viral Particles ◽

Murine Leukemia

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Role of Variable Regions A and B in Receptor Binding Domain of Amphotropic Murine Leukemia Virus Envelope Protein

Journal of Virology ◽

10.1128/jvi.72.11.9101-9108.1998 ◽

1998 ◽

Vol 72 (11) ◽

pp. 9101-9108 ◽

Cited By ~ 24

Author(s):

Jin-Young Han ◽

Yi Zhao ◽

W. French Anderson ◽

Paula M. Cannon

Keyword(s):

Receptor Binding ◽

Envelope Protein ◽

Murine Leukemia Virus ◽

Leukemia Virus ◽

Binding Domain ◽

Receptor Binding Domain ◽

Variable Regions ◽

Amino Terminal ◽

Amphotropic Murine Leukemia Virus ◽

Murine Leukemia

ABSTRACT For the amphotropic murine leukemia virus (MuLV), a 208-amino-acid amino-terminal fragment of the surface unit (SU) of the envelope glycoprotein is sufficient to bind to its receptor, Pit2. Within this binding domain, two hypervariable regions, VRA and VRB, have been proposed to be important for receptor recognition. In order to specifically locate residues that are important for the interaction with Pit2, we generated a number of site-specific mutations in both VRA and VRB and analyzed the resulting envelope proteins when expressed on retroviral vectors. Concurrently, we substituted portions of the amphotropic SU with homologous regions from the polytropic MuLV envelope protein. The amphotropic SU was unaffected by most of the point mutations we introduced. In addition, the deletion of eight residues in a region of VRA that was previously suggested to be essential for Pit2 utilization only decreased titer on NIH 3T3 cells by 1 order of magnitude. Although the replacement of the amino-terminal two-thirds of VRA with the polytropic sequence abolished receptor binding, smaller nonoverlapping substitutions did not affect the function of the protein. We were not able to identify a single critical receptor contact point within VRA, and we suggest that the amphotropic receptor binding domain probably makes multiple contacts with the receptor and that the loss of some of these contacts can be tolerated.

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