Simian immunodeficiency virus envelope glycoprotein counteracts tetherin/BST-2/CD317 by intracellular sequestration.
Tetherin is an IFN-inducible restriction factor that inhibits HIV-1 particle release in the absence of the HIV-1 countermeasure, viral protein U (Vpu). Although ubiquitous in HIV-1 and simian immunodeficiency viruses from chimpanzees, greater spot nosed monkeys, mustached monkeys, and Mona monkeys, other primate lentiviruses do not encode a Vpu protein. Here we demonstrate that SIV from Tantalus monkeys (SIVtan) encodes an envelope glycoprotein (SIVtan Env) able to counteract tetherin from Tantalus monkeys, rhesus monkeys, sooty mangabeys, and humans, but not from pigs. We show that sensitivity to Vpu but not SIVtan Env can be transferred with the human tetherin transmembrane region. We also identify a mutation in the tetherin extracellular domain, which almost completely abolishes sensitivity of human tetherin to SIVtan Env without compromising antiviral activity or sensitivity to Vpu. SIVtan Env expression results in a reduction of surface tetherin, as well as reduction in tetherin co-localization with mature surface-associated virus. Immuno-electron microscopy reveals co-localization of SIVtan Env with tetherin in intracellular tubulo-vesicular structures, suggesting that tetherin is sequestered away from budding virions at the cell surface. Along with HIV-1 Vpu and SIV Nef, envelope glycoprotein is the third and most broadly active lentiviral-encoded tetherin countermeasure to be described. Our observations emphasize the importance of tetherin in protecting mammals against viral infection and suggest that HIV-1 Vpu inhibitors may select active envelope mutants.
Medical Research Council Centre for Medical Molecular Virology, Division of Infection and Immunity, University College London, 46 Cleveland Street, London W1T 4JF, United Kingdom.
Ravindra K
RK
Gupta
Petra
P
Mlcochova
Annegret
A
Pelchen-Matthews
Sarah J
SJ
Petit
Giada
G
Mattiuzzo
Deenan
D
Pillay
Yasuhiro
Y
Takeuchi
Mark
M
Marsh
Greg J
GJ
Towers
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D005110:Extracellular Space / Q000378:metabolism; D058851:GPI-Linked Proteins; D000882:Haplorhini; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D017354:Point Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D015302:Simian Immunodeficiency Virus / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000378:metabolism*; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000378:metabolism; D000074010:Bone Marrow Stromal Antigen 2
D015703:Antigens, CD; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C094572:BST2 protein, human; D000074010:Bone Marrow Stromal Antigen 2