Further investigation of simian immunodeficiency virus Vif function in human cells.
Primate lentivirus Vif proteins function by suppressing the antiviral activity of the cell-encoded apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like (APOBEC) proteins APOBEC3G and APOBEC3F. It has been hypothesized that species-specific susceptibilities of APOBEC proteins to Vif proteins may help govern the transmission of primate lentiviruses to new host species. Consistent with this view and with previous results, we report that the Vif proteins of several diverse simian immunodeficiency viruses (SIVs) that are not known to infect humans are not effective inhibitors of human APOBEC3G or APOBEC3F when assessed in transient-transfection experiments. Unexpectedly, this lack of SIV Vif function did not prevent the replication of two vif-deficient SIVs (SIVtan and SIVmnd1; isolated from tantalus monkeys and mandrills, respectively) in a human T-cell line, HUT78, that expresses both APOBEC 3G and APOBEC3F, a finding which demonstrates that some SIVs are partially resistant to the antiretroviral effects of these enzymes irrespective of Vif function. Additional virus replication studies also revealed that the Vif protein of SIVtan is, in fact, active in human T cells, as it substantially enhanced the replication of its cognate virus and human immunodeficiency virus type 1. In sum, we now consider it improbable that species-specific restrictions to SIV Vif function can explain the lack of human infection with certain SIVs. Instead, our data reveal that the species-specific modulation of Vif function is more complex than previously envisioned and that additional (as-yet-unidentified) viral or host factors may be involved in regulating this dynamic interaction between host and pathogen.
Department of Microbiology, University of Pennsylvania, Philadelphia, USA.
Nathan C
NC
Gaddis
Ann M
AM
Sheehy
K Muneer
KM
Ahmad
Chad M
CM
Swanson
Kate N
KN
Bishop
Brigitte E
BE
Beer
Preston A
PA
Marx
Feng
F
Gao
Frederic
F
Bibollet-Ruche
Beatrice H
BH
Hahn
Michael H
MH
Malim
D000071480:APOBEC-3G Deaminase; D001483:Base Sequence; D002460:Cell Line; D003564:Cytidine Deaminase; D043525:Cytosine Deaminase / Q000235:genetics / Q000502:physiology; D016346:Gene Products, vif / Q000502:physiology*; D006678:HIV / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D009700:Nucleoside Deaminases; D011506:Proteins / Q000235:genetics / Q000502:physiology; D012097:Repressor Proteins; D015302:Simian Immunodeficiency Virus / Q000502:physiology*; D013045:Species Specificity; D013601:T-Lymphocytes / Q000821:virology; D014162:Transfection; D014779:Virus Replication; D054320:vif Gene Products, Human Immunodeficiency Virus
D016346:Gene Products, vif; D011506:Proteins; D012097:Repressor Proteins; D054320:vif Gene Products, Human Immunodeficiency Virus; D009700:Nucleoside Deaminases; C492906:APOBEC3F protein, human; D043525:Cytosine Deaminase; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase