title: Equine infectious anemia virus and the ubiquitin-proteasome system.
abstract: Some retroviruses contain monoubiquitinated Gag and do not bud efficiently from cells treated with proteasome inhibitors, suggesting an interaction between the ubiquitin-proteasome system and retrovirus assembly. We examined equine infectious anemia virus (EIAV) particles and found that approximately 2% of the p9(Gag) proteins are monoubiquitinated, demonstrating that this Gag protein interacts with an ubiquitinating activity. Different types of proteasome inhibitors were used to determine if proteasome inactivation affects EIAV release from chronically infected cells. Pulse-chase immunoprecipitation and time course immunoblot analyses showed that proteasome inactivation slightly decreased virus release (at most a twofold effect), while it did not affect Gag processing. These results contrast with those obtained with other viruses which are sensitive to these inhibitors. This suggests that, although its Gag is monoubiquitinated, the requirements for EIAV release are somewhat different from those for retroviruses that are sensitive to proteasome inhibitors.
authors.affiliation: AIDS Vaccine Program, SAIC Frederick, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland 21702, USA. ott@ncifcrf.gov
authors.forename: David E
authors.initials: DE
authors.lastname: Ott
authors.forename: Lori V
authors.initials: LV
authors.lastname: Coren
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Sowder
authors.forename: Julian
authors.initials: J
authors.lastname: Adams
authors.forename: Kunio
authors.initials: K
authors.lastname: Nagashima
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schubert
mesh_terms: D000818:Animals; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004859:Equine Infectious Anemia / Q000821:virology; D015683:Gene Products, gag / Q000378:metabolism; D004860:Infectious Anemia Virus, Equine / Q000187:drug effects / Q000502:physiology*; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D025801:Ubiquitin / Q000378:metabolism*; D019065:Virus Assembly
chemical_list: D004791:Enzyme Inhibitors; D015683:Gene Products, gag; D009097:Multienzyme Complexes; D025801:Ubiquitin; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex