title: Topoisomerase I activity associated with human immunodeficiency virus (HIV) particles and equine infectious anemia virus core.
abstract: In the present study, we found a topoisomerase I (topo I) activity in two strains of human immunodeficiency virus type 1 (HIV-1) and equine infectious anemia virus (EIAV) particles. The topo I activity was located in the EIAV cores and differed from the cellular topo I in its ionic requirements and response to ATP, indicating that these were two distinct forms of this enzyme. Topo I activity was removed from the viral lysates and viral cores by anti-topo I antiserum. The only protein recognized by this antiserum was an 11.5 kd protein in HIV lysate and 11 kd in EIAV lysate. We showed that the 11 kd protein recognized by the anti-topo I antiserum is the EIAV p11 nucleocapsid protein. Furthermore, purified topo I protein blocked the binding of the antibodies to the p11 protein and vice versa, purified p11 protein blocked the binding of these antibodies to the cellular topo I. These results suggest that the EIAV p11 nucleocapsid protein and the cellular topo I share similar epitopes.
authors.affiliation: Microbiology and Immunology Unit, Faculty of Health Sciences, Ben-Gurion University, Beer-Sheva, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Priel
authors.forename: S D
authors.initials: SD
authors.lastname: Showalter
authors.forename: M
authors.initials: M
authors.lastname: Roberts
authors.forename: S
authors.initials: S
authors.lastname: Oroszlan
authors.forename: S
authors.initials: S
authors.lastname: Segal
authors.forename: M
authors.initials: M
authors.lastname: Aboud
authors.forename: D G
authors.initials: DG
authors.lastname: Blair
mesh_terms: D000906:Antibodies / Q000302:isolation & purification; D015153:Blotting, Western; D002460:Cell Line; D002472:Cell Transformation, Viral; D002846:Chromatography, Affinity; D004264:DNA Topoisomerases, Type I / Q000302:isolation & purification / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D015497:HIV-1 / Q000201:enzymology*; D006801:Humans; D004860:Infectious Anemia Virus, Equine / Q000201:enzymology*; D007700:Kinetics; D008970:Molecular Weight; D013045:Species Specificity
chemical_list: D000906:Antibodies; D004264:DNA Topoisomerases, Type I