Novel Gag-Pol frameshift site in human immunodeficiency virus type 1 variants resistant to protease inhibitors.
Human immunodeficiency virus type 1 (HIV-1) variants resistant to protease inhibitors have been shown to contain a mutation in the p1/p6 Gag precursor cleavage site. At the messenger RNA level, this mutation generates a U UUU UUU sequence that is reminiscent of the U UUU UUA sequence required for ribosomal frameshifting and Gag-Pol synthesis. To test whether the p1/p6 cleavage site mutation was generating a novel frameshift site, HIV sequences were inserted in translation vectors containing a chloramphenicol acetyltransferase (CAT) reporter gene requiring -1 frameshifting for expression. All sequences containing the original HIV frameshift site supported the synthesis of CAT but expression was increased 3- to 11-fold in the presence of the mutant p1/p6 sequence. When the original frameshift site was abolished by mutation, expression remained unchanged when using constructs containing the mutant p1/p6 sequence, whereas it was decreased 2- to 4.5-fold when using wild-type p1/p6 constructs. Similarly, when introduced into HIV molecular clones, the p1/p6 mutant sequence supported Gag-Pol synthesis and protease activity in the absence of the original frameshift site, indicating that this sequence could also promote ribosomal frameshifting in virus-expressing cells.
Doyon
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Bio-Méga Research Division, Boehringer Ingelheim (Canada) Ltd., Laval, Quebec, Canada H7S 2G5.
Payant
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Brakier-Gingras
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Lamarre
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D000595:Amino Acid Sequence; D001483:Base Sequence; D004352:Drug Resistance, Microbial; D016368:Frameshift Mutation; D015685:Fusion Proteins, gag-pol / Q000235:genetics*; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data
D015685:Fusion Proteins, gag-pol; D017320:HIV Protease Inhibitors