Equine Infectious Anemia Virus and the Ubiquitin-Proteasome System
| Autor: | David E. Ott, Kunio Nagashima, Julian Adams, Raymond C. Sowder, Ulrich Schubert, Lori V. Coren |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Proteasome Endopeptidase Complex
viruses Immunology Gene Products gag medicine.disease_cause Microbiology Virus Cell Line Equine infectious anemia Retrovirus Multienzyme Complexes Virology Murine leukemia virus medicine Animals Enzyme Inhibitors Rous sarcoma virus biology Ubiquitin Structure and Assembly Virus Assembly Simian immunodeficiency virus Group-specific antigen biology.organism_classification Virus Release Cysteine Endopeptidases Equine Infectious Anemia Insect Science Infectious Anemia Virus Equine |
| Zdroj: | Journal of Virology. 76:3038-3044 |
| ISSN: | 1098-5514 0022-538X |
| DOI: | 10.1128/jvi.76.6.3038-3044.2002 |
| Popis: | 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. Lentiviruses and type C retroviruses assemble in association with the host plasma membrane, forming a bud that is released from the cell to produce a virion (46). The late assembly domain (L) within Gag is crucial for the efficient release of the budding virus from the plasma membrane (42). Three different sequences have been shown to possess L domain function: PPPY, found in Rous sarcoma virus (RSV) (51, 52), murine leukemia virus (MuLV), (54), and Mason-Pfizer monkey virus (53); PTAP, found in human immunodeficiency virus type 1 (HIV-1) (presumably P[T/S]AP for HIV-2 and simian immunodeficiency virus [SIV]) (11, 18); and YPDL, found in equine infectious anemia virus (EIAV) (34). Deletion or replacement of these sequences causes virions to mostly remain attached to the plasma membrane by a thin tether and to fail to separate from the cell. These L domain sequences can interact directly with cellular proteins (8, 9, 12, 13, 19, 35, 45), suggesting potential cellular partners for virus budding. Despite these findings, the pathway(s) used by retroviruses for budding is mostly unknown, though recent results suggest that components of the vacuolar protein sorting pathway might be used by HIV-1 (9). Experiments with several retroviruses have shown that Gag interacts with the ubiquitination pathway and that efficient budding requires active proteasomes (47). Here we examine EIAV for interactions with the ubiquitin (Ub)-proteasome system. EIAV particles contain free Ub and Ub-Gag conjugates. For |
| Databáze: | OpenAIRE |
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