Simian immunodeficiency virus envelope glycoprotein counteracts tetherin/BST-2/CD317 by intracellular sequestration

Proc Natl Acad Sci U S A. 2009 Dec 8;106(49):20889-94. doi: 10.1073/pnas.0907075106. Epub 2009 Oct 28.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, CD / chemistry
  • Antigens, CD / metabolism*
  • Antigens, CD / ultrastructure
  • Cell Membrane / metabolism
  • Cell Membrane / ultrastructure
  • Extracellular Space / metabolism
  • GPI-Linked Proteins
  • Haplorhini
  • Humans
  • Intracellular Space / metabolism*
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / metabolism*
  • Membrane Glycoproteins / ultrastructure
  • Molecular Sequence Data
  • Point Mutation / genetics
  • Protein Structure, Tertiary
  • Protein Transport
  • Simian Immunodeficiency Virus / metabolism*
  • Viral Envelope Proteins / chemistry
  • Viral Envelope Proteins / metabolism*
  • gag Gene Products, Human Immunodeficiency Virus / metabolism

Substances

  • Antigens, CD
  • BST2 protein, human
  • GPI-Linked Proteins
  • Membrane Glycoproteins
  • Viral Envelope Proteins
  • gag Gene Products, Human Immunodeficiency Virus

Associated data

  • GENBANK/FJ345303
  • GENBANK/FJ527910
  • GENBANK/GQ304749