Assembly, processing, and infectivity of human immunodeficiency virus type 1 gag mutants.
We studied the effects of gag mutations on human immunodeficiency virus type 1 (HIV-1) assembly, processing, and infectivity by using a replication-defective HIV expression system. HIV mutants were screened for infectivity by transduction of a selectable marker and were examined for assembly by monitoring particle release from transfected cells. Gag protein processing and reverse transcriptase activities of mutant particles were also assayed. Surprisingly, most Gag protein mutants were assembled and processed. The two exceptions to this rule were a myristylation-minus mutant, and one gag matrix domain mutant which expressed proteins that were trapped intracellularly. Interestingly, a mutant with a 56-amino-acid deletion within the HIV gag capsid domain still could assemble and process virus particles, exhibited a wild-type retrovirus particle density, and had wild-type reverse transcriptase activity. Indeed, although most HIV-1 gag mutants were noninfectious or poorly infectious, they produced apparently normal particles which possessed significant reverse transcriptase activities. These results strongly support the notion that the HIV-1 Gag proteins are functionally involved in post-assembly, postprocessing stages of virus infectivity.
Wang
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Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201.
Barklis
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002522:Chlorocebus aethiops; D004252:DNA Mutational Analysis; D003902:Detergents; D015683:Gene Products, gag / Q000378:metabolism*; D015750:Genes, gag; D016655:HIV Core Protein p24 / Q000235:genetics / Q000378:metabolism; D054303:HIV Reverse Transcriptase; D015497:HIV-1 / Q000235:genetics / Q000254:growth & development*; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D014771:Virion / Q000737:chemistry; D014779:Virus Replication
D003902:Detergents; D015683:Gene Products, gag; D016655:HIV Core Protein p24; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase