Biological characterization of noninfectious HIV-1 particles lacking the envelope protein.
To understand the role of the HIV-1 envelope protein in the assembly of virus, we constructed a proviral clone of HIV-1 where the methionine initiator codon of the env gene was substituted with a translational stop codon. Upon DNA transfection into permissive cells in culture, this clone produces virus-like particles similar in size to parental virus but are noninfectious in human T-cells, promonocytic cells, and primary macrophages. This mutant readily recombines with a deletion mutant provirus lacking the entire gag-pol region producing a recombinant virus that is infectious. Substitution of the same initiator methionine codon with valine results in a leaky missense mutant provirus capable of a low level of Env protein synthesis that leads to a productive infection. Thus, the prototype initiation codon AUG is dispensable for virus infectivity. Further, the expression of the envelope protein is not a prerequisite for the assembly of the virus particles in the HIV-1 system. These noninfectious envelope-less particles revert readily to wild-type phenotype upon cotransfection with Env-producing plasmid DNAs.
Sadaie
M R
MR
Laboratory of Tumor Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
Kalyanaraman
V S
VS
Mukopadhayaya
R
R
Tschachler
E
E
Gallo
R C
RC
Wong-Staal
F
F
D000818:Animals; D002522:Chlorocebus aethiops; D004252:DNA Mutational Analysis; D003673:Defective Viruses / Q000254:growth & development*; D015686:Gene Products, env / Q000235:genetics*; D015752:Genes, env; D016655:HIV Core Protein p24 / Q000378:metabolism; D015658:HIV Infections / Q000382:microbiology; D015497:HIV-1 / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D066298:In Vitro Techniques; D008264:Macrophages / Q000382:microbiology; D014407:Tumor Cells, Cultured; D014779:Virus Replication
D015686:Gene Products, env; D016655:HIV Core Protein p24