Selection for loss of Ref1 activity in human cells releases human immunodeficiency virus type 1 from cyclophilin A dependence during infection.
Capsid (CA)-specific restrictions are determinants of retroviral tropism in mammalian cells. One such restriction, human Ref1, targets strains of murine leukemia virus bearing an arginine at CA residue 110 (N-MLV), resulting in decreased accumulation of viral cDNA. The cellular factors accounting for Ref1 activity are unknown. As(2)O(3) increases N-MLV titer in Ref1-positive cells, possibly by counteracting Ref1. Restriction factor saturation experiments suggest that Ref1 may also target human immunodeficiency virus type 1 (HIV-1), but only if its CA is not bound to the cellular protein cyclophilin A (CypA). As a step towards understanding the genetic determinants of Ref1, we subjected Ref1-positive TE671 cells to three sequential rounds of selection with N-MLV reporter viruses. We isolated a subclone, 17H1, that was permissive for N-MLV infection and therefore deficient in Ref1 activity. Stimulation of N-MLV replication by As(2)O(3) was attenuated in 17H1, confirming that the drug acts by overcoming Ref1 activity. HIV-1 infection of 17H1 cells was resistant to disruption of the CA-CypA interaction, demonstrating that Ref1 restricts CypA-free HIV-1. Our results suggest that interaction with CypA evolved to protect HIV-1 from this human antiviral activity.
Departmetn of Microbiology, Columbia University College of Physicians and Surgeons, 701 W. 168th St., New York, NY 10032, USA.
David M
DM
Sayah
Jeremy
J
Luban
D000090103:Antiviral Restriction Factors; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology; D002352:Carrier Proteins / Q000502:physiology; D045744:Cell Line, Tumor; D021984:Cyclophilin A / Q000502:physiology*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000502:physiology*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D010087:Oxides / Q000494:pharmacology; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases
D000090103:Antiviral Restriction Factors; D001152:Arsenicals; D002352:Carrier Proteins; D010087:Oxides; D000070584:Tripartite Motif Proteins; C477346:TRIM5 protein, human; D044767:Ubiquitin-Protein Ligases; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D021984:Cyclophilin A; D000077237:Arsenic Trioxide