Isolation and characterization of infectious full-length DNA clones of chimpanzee foamy viruses SFV6 and SFV7: evidence for a Taf-dependent internal promoter.
We have cloned complete viral genomes directly from Hirt supernatant DNAs of simian foamy virus types 6 and 7 (SFV6 and SFV7) -infected cells. These clones were shown to be infectious by transfection into cells and subsequent infection of susceptible cells either by cocultivation or by passage of cell-free supernatants. The presence of virus particles, suggested by a typical cytopathic effect, was confirmed by electron microscopy. These viruses were characterized at different levels of the replication cycle. The proviral genomes revealed a taf deletion comparable to that previously described in the human foamy virus (HFV) bel1 gene. Analysis of viral RNAs revealed similar patterns of transcripts for SFV6- and SFV7-infected cells, with predominant expression of accessory genes. Characteristic major viral polypeptides were identified by radioimmunoprecipitation for both isolates. Sequences homologous to the gene encoding Taf and to a potential internal promoter were identified in the infectious clones and subcloned into expression vectors. Their functional properties were tested by transfection assays, which provided evidence for the presence of a Taf-dependent internal promoter in both SFV6 and SFV7 isolates.
Tobaly-Tapiero
J
J
UPR A0043, CNRS Rétrovirus et Rétrotransposons des Vertébrés, Hôpital Saint-Louis, Paris.
De Celis-Kosmas
J
J
Bittoun
P
P
Lasneret
J
J
Poorters
A M
AM
Eladari
M E
ME
Emanoil-Ravier
R
R
D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D006224:Cricetinae; D004274:DNA, Recombinant; D004279:DNA, Viral; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004285:Dogs; D006801:Humans; D008253:Macaca mulatta; D002679:Pan troglodytes / Q000821:virology; D011401:Promoter Regions, Genetic; D011533:Proviruses / Q000235:genetics; D012191:Retroviridae Proteins / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D016092:Spumavirus / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism / Q000648:ultrastructure; D015534:Trans-Activators / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D004274:DNA, Recombinant; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D012191:Retroviridae Proteins; D015534:Trans-Activators; C074061:bel1 protein, Human foamy virus