Role of Nedd4 and Ubiquitination of Rous Sarcoma Virus Gag in Budding of Virus-Like Particles from Cells

• DOI: 10.1128/jvi.78.24.13943-13953.2004
• Publication Date: 2004-11-24T21:57:59Z
• Authors: Marcy L. Vana; Yi Tang; Aiping Chen; Gisselle Medina; Carol Carter; Jonathan Leis
• Keywords: Rous sarcoma virus; NEDD4; Budding; VP40; Group-specific antigen

Rous sarcoma virus (RSV) budding requires an interaction of the L domain within p2b region Gag with cellular Nedd4-family E3 ubiquitin protein ligases. Members our laboratories previously demonstrated that overexpression a fragment chicken Nedd4-like (LDI-1 WW) inhibits release in dominant-negative manner (A. Kikonyogo, F. Bouamr, M. L. Vana, Y. Xiang, A. Aiyar, C. Carter, and J. Leis, Proc. Natl. Acad. Sci. USA 98:11199-11204, 2001). We have now identified complete 3' end LDI-1 determined it has C-terminal ligase HECT domain, similar to other Nedd4 family members. While full-length clone FL) had little effect on budding, FL mutant substitution catalytic site blocked release, WW. The coexpression hemagglutinin-tagged (HA-Ub) resulted detection mono- polyubiquitinated forms cells mostly monoubiquitinated virus-like particles (VLPs). When Nedd4-binding (L domain) was deleted, ubiquitinated not detected. Interestingly, covalently linked C terminus (Gag-Ub) still by To understand mechanism this inhibition, we examined expressing WW electron microscopy. In presence WW, VLPs were found electron-dense inclusion bodies cytoplasm transfected cells. contrast, when coexpressed Gag-Ub examined, detected but did contain VLPs. These results indicate ubiquitination is dependent upon binding suggest additional functions during RSV besides Gag.