Identification of the HIV-1 NC binding interface in Alix Bro1 reveals a role for RNA

Tuesday, October 09, 2012 — Poster Session I
1:00 p.m. – 3:00 p.m	Natcher Conference Center, Building 45	NIAID	VIROL-15

* FARE Award Winner

Authors

• P Sette
• V Dussupt
• F Bouamr

Abstract

HIV-1 recruits members of ESCRT, the cell membrane fission machinery that promote virus exit. HIV-1 Gag protein gains access to ESCRT by binding Alix, an ESCRT-associated protein that promotes budding. The Alix Bro1 and V domains bind Gag NC and p6 regions, respectively. Whereas the V-p6 binding and function are well characterized, residues in Bro1 that interact with NC and their functional contribution to Alix-mediated HIV-1 budding are unknown. We mapped Bro1 residues that constitute NC binding interface and found they are critical for function. Intriguingly, residues involved in interactions on both sides of the Bro1-NC interface are positively charged, suggesting the involvement of a negatively charged cellular factor serving as a bridge. Nuclease treatment eliminated Bro1-NC interactions revealing involvement of RNA. These findings establish a direct role for NC in mediating interactions with ESCRT necessary for virus release, and report the first evidence of RNA involvement in such recruitment.

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