Genetic evidence that the Tat proteins of human immunodeficiency virus types 1 and 2 can multimerize in the eukaryotic cell nucleus.
The formation of dimers or higher-order multimers is critical to the biological activity of many eukaryotic regulatory proteins. However, biochemical analyses of the multimerization capacity of the Tat trans activator of human immunodeficiency virus types 1 (HIV-1) and 2 (HIV-2) have yielded contradictory results. We used the two-hybrid genetic assay for protein-protein interactions in the eukaryote Saccharomyces cerevisiae (S. Fields and O.-K. Song, Nature [London] 340:245-246, 1989) to examine the multimerization of Tat in vivo. Both HIV-1 and HIV-2 Tat are shown to form specific homo- but not heteromultimers in the yeast cell nucleus. Mutational analysis indicates a critical role for the essential core motif of Tat in mediating this interaction but demonstrates that efficient Tat multimerization does not require an intact cysteine motif. These data raise the possibility that the multimerization of Tat may be important for Tat function in higher eukaryotes.
Bogerd
H P
HP
Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710.
Fridell
R A
RA
Blair
W S
WS
Cullen
B R
BR
D002467:Cell Nucleus / Q000378:metabolism*; D015825:Chromosomes, Fungal; D003001:Cloning, Molecular / Q000379:methods; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015696:Gene Products, tat / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D015498:HIV-2 / Q000378:metabolism*; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism; D054322:tat Gene Products, Human Immunodeficiency Virus
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D015696:Gene Products, tat; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D054322:tat Gene Products, Human Immunodeficiency Virus; D001616:beta-Galactosidase