부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.virol.2009.07.031 Byline: Iris Cadima-Couto (a)(b), Acilino Freitas-Vieira (a)(b), Roni Nowarski (c), Elena Britan-Rosich (c), Moshe Kotler (c), Joao Goncalves (a)(b) Keywords: APOBEC3G; HIV-1Vif; Ubiquitin; N-end rule Abstract: The human APOBEC3G (A3G) is a potent inhibitor of HIV-1 replication and its activity is suppressed by HIV-1 virion infectivity factor (Vif). Vif neutralizes A3G mainly by inducing its degradation in the proteasome and blocking its incorporation into HIV-1 virions. Assessing the time needed for A3G incorporation into virions is, therefore, important to determine how quickly Vif must act to induce its degradation. We show that modelling the intracellular half-life of A3G can induce its Vif-independent targeting to the ubiquitin-proteasome system. By using various amino acids (X) in a cleavable ubiquitin-X-A3G fusion, we demonstrate that the half-life (t1/2) of X-A3G can be manipulated. We show that A3G molecules with a half-life of 13 min are incorporated into virions, whereas those with a half-life shorter than 5 min were not. The amount of X-A3G incorporated into virions increases from 13 min (Phe-A3G) to 85 min (Asn-A3G) and remains constant after this time period. Interestingly, despite the presence of similar levels of Arg-A3G (t1/2=28 min) and Asp-A3G (t1/2=65 min) into HIV-1 [DELTA]vif virions, inhibition of viral infectivity was only evident in the presence of A3G proteins with a longer half-life (t1/2[greater than or equal to]65 min). Author Affiliation: (a) URIA-Centro Patogenese Molecular, Faculdade de Farmacia da Universidade Lisboa, Av. Das Forcas Armadas, Lisboa 1649-059, Portugal (b) Instituto de Medicina Molecular, Lisboa, Portugal (c) Department of Pathology and the Lautenberg Center for General and Tumor Immunology, the Hebrew University, Hadassah Medical School, Jerusalem 91120, Israel Article History: Received 17 May 2009; Revised 23 June 2009; Accepted 24 July 2009