Disruption of the putative splice acceptor site for SIV(mac239)Vif reveals tight control of SIV splicing and impaired replication in Vif non-permissive cells.
Vif is dispensable for simian immunodeficiency virus (SIV) replication in some cells, termed permissive (i.e., CEM-SS), but not in others, termed non-permissive (i.e., H9, CEMx174, and peripheral blood lymphocytes). Non-permissive cells express the RNA editing enzyme, APOBEC3G. To determine whether vif mRNA could be alternatively spliced, a mutation altering the putative vif splice acceptor site (SA1) was introduced into SIV(mac239) (SIV(Deltavif-SA)). Despite three consensus splice acceptor sites nearby SA1, SIV(Deltavif-SA) did not efficiently generate alternatively spliced vif mRNA. SIV(Deltavif-SA) was growth attenuated in CEMx174 and H9 cells but not in CEM-SS cells. Following SIV(Deltavif-SA), but not SIV(mac239), infection in either H9 or CEMx174 cells viral cDNA contained numerous G to A mutations; no such differences were observed in CEM-SS cells. This pattern is consistent with mutations generated by APOBEC3G in the absence of Vif. Therefore, efficient splicing of SIV vif mRNA is tightly controlled and requires the SA1 site.
Victoria
Joseph G
JG
Department of Microbiology and Molecular Genetics, University of California, Irvine, CA 92697-4800, USA.
Robinson
W Edward
WE
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D016384:Consensus Sequence; D004261:DNA Replication; D016346:Gene Products, vif / Q000235:genetics*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics; D015302:Simian Immunodeficiency Virus / Q000235:genetics*; D014158:Transcription, Genetic
D016346:Gene Products, vif; D012333:RNA, Messenger; D012367:RNA, Viral