Proposed gag-encoded transcriptional activator is not necessary for Rous sarcoma virus replication or transformation.
It has been reported that gene expression directed by the long terminal repeat of Rous sarcoma virus (RSV) is trans activated by a protein encoded in an alternate reading frame within the RSV gag gene (S. Broome and W. Gilbert, Cell 40:537-546, 1985). We have made specific mutations to test the role of the putative transcriptional activator in RSV replication. Termination codons were created within the alternate reading frame coding for the trans activator, and the mutations were introduced into an infectious RSV plasmid. We were unable to demonstrate specific trans activation of the RSV long terminal repeat by either wild-type or mutant RSV plasmids in transient cotransfection assays. Experiments using mutant or wild-type RSV-infected chick embryo fibroblasts indicated that the proposed RSV transcriptional activator was not required for viral replication or transformation and did not increase steady-state levels of viral RNA.
Carlberg
K
K
Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218.
Beemon
K
K
D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D015683:Gene Products, gag; D005814:Genes, Viral; D009154:Mutation; D010957:Plasmids; D012367:RNA, Viral / Q000032:analysis; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D012191:Retroviridae Proteins / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology; D014162:Transfection; D010948:Viral Plaque Assay; D014779:Virus Replication
D015683:Gene Products, gag; D012367:RNA, Viral; D012191:Retroviridae Proteins; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase; D012194:RNA-Directed DNA Polymerase