Dominant negative mutants of human T-cell leukemia virus type I Rex and human immunodeficiency virus type 1 Rev fail to multimerize in vivo.
Human T-cell leukemia virus type I (HTLV-I) Rex and human immunodeficiency virus type 1 (HIV-1) Rev are essential gene products required for the replication of these two pathogenic human retroviruses. Both Rex and Rev act at a posttranscriptional level by binding to highly structured RNA-response elements, the Rex-response element in HTLV-I and the Rev-response element in HIV-1. Using a sensitive in vivo assay of protein-protein interaction, we now demonstrate that the HTLV-I Rex and HIV-1 Rev proteins readily form homomultimeric complexes in the absence of their cognate RNA-response elements yet fail to form heteromultimeric complexes with each other. Dominant negative mutations have been identified in both the rex and rev genes which presumably specify a critical activation or effector domain in each of these viral transactivators. Surprisingly, these dominant negative mutants of Rex and Rev fail to interact in vivo. These findings raise the possibility that the binding of nonfunctional monomers rather than functional multimers underlies the transdominant phenotype of these Rex and Rev mutants. Further, it seems likely that the assembly of functional and stable multimers of Rex and Rev in vivo may depend not only on the intrinsic multimerization domains of these proteins but also on the binding of a bridging cellular cofactor to the related activation domains present in each viral transactivator.
Bogerd
H
H
Department of Medicine, Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710.
Greene
W C
WC
D000163:Acquired Immunodeficiency Syndrome / Q000235:genetics*; D000595:Amino Acid Sequence; D015500:Chloramphenicol O-Acetyltransferase / Q000032:analysis; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics; D015694:Gene Products, rev / Q000235:genetics / Q000378:metabolism*; D016370:Gene Products, rex / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics*; D017405:Herpes Simplex Virus Protein Vmw65 / Q000235:genetics; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D015533:Transcriptional Activation; D014162:Transfection; D054321:rev Gene Products, Human Immunodeficiency Virus
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D015694:Gene Products, rev; D016370:Gene Products, rex; D017405:Herpes Simplex Virus Protein Vmw65; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D054321:rev Gene Products, Human Immunodeficiency Virus; D015500:Chloramphenicol O-Acetyltransferase