title: HIV-1 Gag co-opts a cellular complex containing DDX6, a helicase that facilitates capsid assembly.
abstract: To produce progeny virus, human immunodeficiency virus type I (HIV-1) Gag assembles into capsids that package the viral genome and bud from the infected cell. During assembly of immature capsids, Gag traffics through a pathway of assembly intermediates (AIs) that contain the cellular adenosine triphosphatase ABCE1 (ATP-binding cassette protein E1). In this paper, we showed by coimmunoprecipitation and immunoelectron microscopy (IEM) that these Gag-containing AIs also contain endogenous processing body (PB)-related proteins, including AGO2 and the ribonucleic acid (RNA) helicase DDX6. Moreover, we found a similar complex containing ABCE1 and PB proteins in uninfected cells. Additionally, knockdown and rescue studies demonstrated that the RNA helicase DDX6 acts enzymatically to facilitate capsid assembly independent of RNA packaging. Using IEM, we localized the defect in DDX6-depleted cells to Gag multimerization at the plasma membrane. We also confirmed that DDX6 depletion reduces production of infectious HIV-1 from primary human T cells. Thus, we propose that assembling HIV-1 co-opts a preexisting host complex containing cellular facilitators such as DDX6, which the virus uses to catalyze capsid assembly.
authors.affiliation: Department of Global Health, University of Washington, Seattle, WA 98102, USA.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Reed
authors.forename: Britta
authors.initials: B
authors.lastname: Molter
authors.forename: Clair D
authors.initials: CD
authors.lastname: Geary
authors.forename: John
authors.initials: J
authors.lastname: McNevin
authors.forename: Julie
authors.initials: J
authors.lastname: McElrath
authors.forename: Samina
authors.initials: S
authors.lastname: Giri
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Klein
authors.forename: Jaisri R
authors.initials: JR
authors.lastname: Lingappa
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000818:Animals; D060565:Argonaute Proteins / Q000378:metabolism; D019556:COS Cells; D002213:Capsid / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D015683:Gene Products, gag / Q000235:genetics* / Q000378:metabolism; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D016253:Microscopy, Immunoelectron / Q000379:methods; D009154:Mutation; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D013601:T-Lymphocytes / Q000201:enzymology
chemical_list: C501917:ABCE1 protein, human; C466422:AGO2 protein, human; D018528:ATP-Binding Cassette Transporters; D060565:Argonaute Proteins; D015683:Gene Products, gag; D011518:Proto-Oncogene Proteins; C094683:DDX6 protein, human; D053487:DEAD-box RNA Helicases