Point mutations in Moloney murine leukemia virus envelope protein: effects on infectivity, virion association, and superinfection resistance.
Retroviral envelope proteins are synthesized in the infected cell and targetted to the assembling virion; during infection, they mediate receptor binding and fusion of the virion and cell membranes. We have generated a series of mutants of the Moloney murine leukemia virus (M-MuLV) with alterations in the TM protein, p15E, and determined whether the mutants are defective for replication and where the defects lie. Twenty-one point mutants were assessed for infectivity, virion-associated envelope protein levels, and the ability to confer resistance to superinfection. Only one mutant was specifically defective in a post-receptor binding step. Three other mutants encoded virion-associated envelope proteins that could not confer resistance to superinfection, implying that they could not bind to the receptor. These mutants demonstrate that in M-MuLV, receptor binding and early events such as membrane fusion can be affected by amino acid changes in the TM protein.
Howard Hughes Medical Institute, Columbia University College of Physicians and Surgeons, New York, New York 10032.
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Berkowitz
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D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D015686:Gene Products, env / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D017354:Point Mutation; D011991:Receptors, Virus / Q000378:metabolism; D015163:Superinfection / Q000235:genetics; D014162:Transfection; D014771:Virion / Q000254:growth & development; D014774:Virulence
D015686:Gene Products, env; D011991:Receptors, Virus