title: A novel minimal in vitro system for analyzing HIV-1 Gag-mediated budding.
abstract: A biomimetic minimalist model membrane was used to study the mechanism and kinetics of cell-free in vitro HIV-1 Gag budding from a giant unilamellar vesicle (GUV). Real-time interaction of Gag, RNA, and lipid, leading to the formation of mini-vesicles, was measured using confocal microscopy. Gag forms resolution-limited punctae on the GUV lipid membrane. Introduction of the Gag and urea to a GUV solution containing RNA led to the budding of mini-vesicles on the inside surface of the GUV. The GUV diameter showed a linear decrease in time due to bud formation. Both bud formation and decrease in GUV size were proportional to Gag concentration. In the absence of RNA, addition of urea to GUVs incubated with Gag also resulted in subvesicle formation. These observations suggest the possibility that clustering of GAG proteins leads to membrane invagination even in the absence of host cell proteins. The method presented here is promising, and allows for systematic study of the dynamics of assembly of immature HIV and help classify the hierarchy of factors that impact the Gag protein initiated assembly of retroviruses such as HIV.
authors.affiliation: Department of Physics & Astronomy, University of California, Riverside, CA, 92521, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Gui
authors.forename: Sharad
authors.initials: S
authors.lastname: Gupta
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.forename: Roya
authors.initials: R
authors.lastname: Zandi
authors.forename: Sarjeet
authors.initials: S
authors.lastname: Gill
authors.forename: I-Chueh
authors.initials: IC
authors.lastname: Huang
authors.forename: A L N
authors.initials: AL
authors.lastname: Rao
authors.forename: Umar
authors.initials: U
authors.lastname: Mohideen
mesh_terms: D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000821:virology; D015497:HIV-1 / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D007700:Kinetics; D012367:RNA, Viral / Q000378:metabolism; D053835:Unilamellar Liposomes / Q000378:metabolism*; D014508:Urea / Q000494:pharmacology; D057074:Virus Release / Q000187:drug effects; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*
chemical_list: D012367:RNA, Viral; D053835:Unilamellar Liposomes; D054301:gag Gene Products, Human Immunodeficiency Virus; D014508:Urea