title: Cellular topoisomerase I activity associated with HIV-1.
abstract: Topoisomerase I activity was detected in detergent-disrupted human immunodeficiency virus type 1 (HIV-1) particles. The enzyme did not require ATP for its conversion of SC DNA to an RC form, had divalent cation requirements similar to those of eukaryotic topoisomerase I, and was significantly inhibited by the specific topoisomerase I inhibitor camptothecin. However, camptothecin failed to inhibit replication of HIV in infected cells at nontoxic concentrations, and an active site motif for topoisomerase I could not be detected on the HIV genome. These results suggests that HIV does not encode a novel topoisomerase I, but rather packages the cellular enzyme.
authors.affiliation: Virology Department, Fairfield Hospital, Victoria, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Jardine
authors.forename: G
authors.initials: G
authors.lastname: Tachedjian
authors.forename: S
authors.initials: S
authors.lastname: Locarnini
authors.forename: C
authors.initials: C
authors.lastname: Birch
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D002166:Camptothecin / Q000494:pharmacology; D002460:Cell Line; D016384:Consensus Sequence; D004264:DNA Topoisomerases, Type I / Q000235:genetics / Q000378:metabolism*; D015658:HIV Infections / Q000201:enzymology / Q000382:microbiology; D015497:HIV-1 / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D059004:Topoisomerase I Inhibitors; D014779:Virus Replication / Q000187:drug effects
chemical_list: D059004:Topoisomerase I Inhibitors; D004264:DNA Topoisomerases, Type I; D002166:Camptothecin